History of our understanding of Atomic...

Hetero means different.

Homo means same.

Soluble means able to dissolve

Insoluble means not able to dissolve

BASIC CHEMICAL DEFINITIONSChemists make a distinction between substances and mixtures.

Substance – pure, containing only one type of particle. A particle could be an element or a compound.Element – one type of atomCompound – one type of molecule or crystal

Mixture – contains 2 or more types of particles that have not been chemically combined

Mixtures fall into two categories based on the distribution of particles: Heterogeneous mixture- a mixture in which there is an uneven

distribution of materialso sand in watero tossed salado oil in water

Homogeneous mixture – a mixture in which all of the particles are evenly distributed

o One example is salt watero Homogeneous mixtures are commonly referred to as solutions. In

a solution one type of particle spreads out to fill the spaces between the particles of a second substance.

o A homogeneous mixture has a solute and a solvent Solute – substance that is being dissolved Solvent – substance that is used to dissolve a second

substance Most common solvents are water and alcohol.

In salt water salt is the solute and water is the solventMixturemore than 1 kind of particleSubstance1 kind of particle

HISTORY OF OUR UNDERSTANDING OF ATOMIC STRUCTURE:

GREEK PHILOSOPHERS:

460 – 380 BC DEMOCRITUS:

He came to the conclusion that matter could not be divided up into smaller and smaller pieces forever. Eventually the smallest possible piece would be obtained, he called this particle the atom. The word atom comes from the Greek word atomos which means “not to be cut or indivisible”.

384 – 322 BC ARISTOTLE:

All things are made up of 4 elements, earth, air, fire and water. The proportions of these elements present determines something’s properties.

The followers of Democritus, called the Atomists, debated Aristotle and lost the debate resulting in the acceptance of Aristotle’s ideas for the next 2000 years.

DEVELOPMENT OF SCIENTIFIC CONCEPTS

1766 – 1844 JOHN DALTON: Was an English chemist who based on experimentation and a review of the scientific findings of the time came up with a new concept of the atom, based on 4 atomic laws:

1. All elements are composed of atoms. Atoms are indivisible and indestructible particles. (He gave credit to Democritus for this idea.)

2. There are as many different kinds of atoms as there are elements. Atoms of the same element are exactly alike. Atoms of different elements are different.

3. Compounds are formed by the joining of atoms of two or more elements. The smallest particle of a compound is called a molecule.

4. Chemical changes involve whole atoms or groups of atoms, but never fractions of atoms.

Dalton’s model became the foundation of modern chemistry but eventually modifications were required.

1897 – JOSEPH J. THOMSON

The first to show atoms were made of smaller particles. He was responsible for finding the electron (negative charge).He described the already known neutral atom to be a pudding-like positively charged material throughout which negatively charged electrons were scattered, like plum-pudding with raisins.

1903 – ERNEST RUTHERFORD:

Ernest Rutherford, English physicist in 1908. While conducting an experiment involving firing a stream of tiny positively charged particles at a thin sheet of gold foil, he discovered most of his positively charged “bullets” passed right through the gold. How could this be the case if there were a lot of scattered protons? (only a few bounced back, straight back). He realized the atom’s positive charged particles were contained in the nucleus. The negatively charged electrons were scattered outside the nucleus at the atom’s edge. (Discovered protons)

1913 - NIELS BOHR: Electrons move in definite orbits around the nucleus, much like planets circle the sun. These orbits, or energy levels, are located at certain distances from the nucleus.

Each orbit has a limited number of electrons that can occupy that orbit. These limits are:

1st orbit = 2 e- 2nd orbit = 8 e-

3rd orbit = 18 e- 4th orbit = 32 e- 5th orbit = 32 e- 6th orbit = 18 e-

7th orbit = 8 e-

With a special additional limit that no outer most orbit can hold more than 8 e-.

1932 – JAMES CHADWICKDiscovered neutrons.

ATOMIC MODEL (BOHR-RUTHERFORD MODEL) AS OF 1932:

QUANTUM THEORY (ELECTRON CLOUD THEORY)

Based on their energy and on probability electrons occupy a cloud-like region about the nucleus in which they will most likely

REVIEW: HISTORY OF ATOMIC STRUCTURE

MATCH

1. _______ Discovered atoms had a nucleus and electrons went around it.

2. _______ Model that says electrons move in “clouds” around nucleus

3. _______ Came up with theory of a “smallest” particle and called it an “atom

4. _______ Thomson’s model of an atom being like a positively charged squish jelly

with negative electrons floating around inside it like raisons

5. _______ An atom can have no more that eight of these

6. _______ Believed there were only four true elements: fire, water, earth, and air.

7. _______ Discovered electrons moved around nucleus in “orbitals.”

8. _______Greek word that means you can’t cut or divide it any further

9. _______ James Chadwick discovered these in 1932

10. _______ Atoms of the same _____________ are alike

11. _______ Created by the joining of more than one element

A. Atom

B. Molecule

C. Valence electrons

D. Neutrons

E. Compound

F. Element

G. Plum Pudding Model

H. Quantum Theory

I. Democritus, 400 BC

J. Rutherford, 1903

K. Bohr, 1913

L. Aristotle, 350 BC

12. _______ The smallest part of a compound

ATOMIC STRUCTUREWhat are the three main subatomic particles? Proton, neutron, electron 99.9% of atomic mass is in nucleus.

PROTONS:

positively charged particles in nucleus The mass of a proton is 1 amu. (atomic mass unit) # of protons never changes . All atoms of the same element have the same # of protons.

NEUTRONS:

found in the nucleus of the atom neutral in charge. slightly more mass than protons but considered to have a mass of 1amu.

ELECTRONS:

a negative charge. located outside the nucleus Each level has different amounts of energy Electrons with lowest energy level are closest to the nucleus. Mass of an electron is 1/1836 amu

ATOMIC NUMBER:

The number of protons in the nucleus Determines what the element is. i.e- an atom of carbon has 6 protons in its nucleus. Find the atomic numbers on a periodic table. Found on the bottom left corner

ISOTOPES:

atoms of the same element with same number of protons but different numbers of neutrons The atomic number is same for isotopes of an element.

ATOMIC MASS:

the sum of the protons and neutrons in nucleus. average mass of all the isotopes of that element it is usually not a whole number, because it is an ave. For example, the atomic mass of carbon is 12.011. Found in upper left corner, usually a decimal

The Atoms Family Song1st Verse:They’re tiny and they’re teeny,Much smaller than a beany,They never can be seeny,The Atoms Family.Chorus

2nd Verse:Together they make gases,And liquids like molasses,And all the solid masses,The Atoms FamilyChorus

3rd Verse:Neutrons can be found,Where protons hang around;Electrons they surroundThe Atoms Family.Chorus

Chorus:They are so small. (Snap, snap)They’re round like a ball. (Snap, snap)They make up the air.They’re everywhere.Can’t see them at all. (Snap, snap)

Particle ChargeMass (in amu’s)

Symbol including charge

Location in atom Other

proton

electron

neutron

REVIEW: HISTORY OF ATOMIC STRUCTURE

Based on your reading, fill out the chart below

What does amu stand for? __________________________________________

Using the Bohr-Rutherford model, draw a picture of an atom with 3 protons, 2 neutrons, and 3 electrons.

Looking at the periodic table of elements, can you guess what element you drew? _________________________

ISOTOPES & SYMBOLSTWO DEFINITIONS

1. Atoms whose nuclei contain the same # of protons, but a different # of neutrons2. Atoms with the same atomic number, but different mass numbers.

Example: Hydrogen – 1 1 p+ 0 no Atomic Number = 1, Mass Number = 1 Hydrogen – 2 1 p+ 1 no Atomic Number = 1, Mass Number = 2 Hydrogen – 3 1 p+ 2 no Atomic Number = 1, Mass Number = 3

All are isotopes of Hydrogen. The number following the name is the Mass Number for the isotope.

Differences in mass have little effect on an atom’s chemical and physical properties. However, different isotopes will have very different nuclear properties.

Example: Uranium – 235 when hit by a neutron splits to form Krypton, Barium and 3 neutrons while releasing

large amounts of energy. Uranium – 238 when hit by a neutron absorbs the neutron to become Uranium – 239.

ISOTOPIC SYMBOL-

Isotopic symbols are a shorthand way to tell the mass number and atomic number of one atom of an element.

Basic Format:

Example 1:

Example 2: #p+ = 23, #n0 = 28

Atomic # = 23, Mass # = 51, #e- = 23, Element is Vanadium

Isotopic Symbol is

STEPS TO DRAWING ATOMS:

EXAMPLE 1: H12

1. Draw a circle to represent the nucleus

2. Enter the number of protons and neutrons into the nucleus

3. Draw a circle to represent each orbit needed around the nucleus (the number of orbits needed is equal to the number of the row the element being drawn is in on the Periodic Table)

4. Enter the electrons on each orbit starting from the orbit closest to the nucleus and working out from there. Be careful to obey Bohr’s limits while adding electrons. (2, 8, 18, Max. 8 in the outer)

EXAMPLE 2: 2914SI

Step 1: Step 2: Step 3:

Finished model: or

DRAWING ATOMS WORKSHEET #1

For each atom below list the Atomic Number, Mass Number, # p+, # e-, and #no. Then draw a Bohr-Rutherford Model of each atom.

1) 2412Mg

Atomic # ______Mass # ______# protons ______# electrons ______# neutrons ______

2) 94Be


3) 3216S


4) 3919K


5) 168O


6) 2512Mg


7) 2010Ne


8) 4019K


9) 4018Ar


10) 3316S


11) 4120Ca


12) 178O



For each atom below write its Isotopic Symbol and name. Draw a Bohr-Rutherford Model of each atom.

1) 13 p+, 14 no 2) 19 p+, 19 no 3) 5 p+, 6 no

4) 6 p+, 8 no 5) 1 p+, 2 no 6) 13 p+, 15 no

7) 2 p+, 2 no 8) 20 p+, 20 no 9) 9 p+, 10 no

10) 18 p+, 21 no 11) 19 p+, 22 no 12) 3 p+, 4 no


For each atom below write its Isotopic Symbol and name. Draw a Bohr-Rutherford Model of each atom.

1) 15 p+, 19 no 2) 16 p+, 13 no 3) 15 p+, 20 no

4) 4 p+, 6 no 5) 17 p+, 23 no 6) 10 p+, 7 no

7) 18 p+, 20 no 8) 5 p+, 6 no 9) 20 p+, 19 no

10) 3 p+, 2 no 11) 12 p+, 13 no 12) 20 p+, 21 no

ISOTOPES WORKSHEET #1

List the Name, Atomic Number (# of protons), & Mass Number, for each of the following atoms.

1) 73 Ge 2) 118 Sn 32 50

3) 30 Si 4) 190 Os 14 76

5) 24 Na 6) 89 Y 11 39

7) 15 N 8) 184 W 7 74

9) 126 I 10) 173 Yb 53 70

11) 57 Fe 12) 174 Lu 26 71

ISOTOPES WORKSHEET #2

Write an isotopic symbol for the atoms described below. Name the element.

1) 39 no, 33 p+ 2) 136 no, 86 p+

3) 61 no, 47 p+ 4) 28 no, 23 p+

5) 149 no, 79 p+ 6) 42 n no o, 33 p+

7) 8 no, 9 p+ 8) 5 no, 4 p+

9) 21 no, 18 p+ 10) 30 no, 27 p+

11) 111 no, 75 p+ 12) 120 no, 80 p+

ISOTOPES LOGIC PUZZLE #1

ISOTOPES LOGIC PUZZLE #2

Normal Atom#P+ = #e-

Net charge = 0

Ion: Charged atom

Ionization Energy: Energy required to remove

electrons

IONS: Ionization is the process by which an atom becomes “charged,” either positively or negatively.

The normal state of an atom is neutral due to balance of P+ and e-

Atoms like having their outer shells complete, or” filled.” They will either borrow electrons from other atoms or give away electrons to make their outer shell full. Gaining or loosing electrons make and atom into an “ion,” a charged atom. When an atom becomes an ion it is attempting to arrive at a stable electron configuration.

If an atom gains electrons (e-) it becomes negatively chargedIf an atom looses electrons, it becomes positively charged. (It now has more p+ than e-)

The outer shell of an atom is called the “valence shell” and electrons in the outer shell are called “valence electrons.” If there are less than four valence electrons it is easier for the atom to give away its electrons to reach a completely filled shell. If there are more than four valence electrons, it is easier for the atom to take electrons from another atom to fill its outer shell. Remember: An atom will gain or lose electrons in order to have an outermost orbit of 8 electrons!!!!

It takes work to lose an electron. Recall that just like north and south magnets are attracted to each other, the electrons are attracted to the protons. To lose and electron the protons and electrons have to be pulled apart. This work is called “ionization energy.”

Make the connection: Remember how rubbing your feet on the carpet can create static electricity by friction? The motion energy your body provides by rubbing is used to loosen the electrons from the atoms in the carpet and they transfer into your body. Your atoms become negative ions because they have extra electrons. Remember that the movement of electrons is “electricity” or electrical energy. When the electrons move out of your body into whatever you shock, your atoms return to neutral.

REVIEW

Draw the atom. Then circle the stable atoms. Put a star next to neutral atoms.1) 13 p+, 14 no, 10 e- 2) 19 p+, 19 no, 18 e- 3) 5 p+, 6 no, 2 e-

4) 6 p+, 8 no, 6 e- 5) 1 p+, 2 no, 1 e- 6) 17 p+, 15 no, 18 e-

CHARGED ATOMS

Directions: For each of the following, determine whether the ion is positive or negative. Write the symbol for the ion with its charge.

Ex. Zinc with 28 electrons. Since: 30 - 28 = +2 Zinc is a positive ion with a symbol of Zn2+

THE PERIODIC TABLE OF ELEMENTSTHE HISTORY OF THE PERIODIC TABLE:

We have been using the periodic table; now let’s take a look at how it was developed. During the 1800’s chemists were discovering many new elements and found they needed some way to organize the data they were coming up with.

JACOB BERZELIUS : ABOUT 1800. He was Swedish. He developed the system for writing chemical symbols.2-rules:

1. 1st letter in a symbol is always capitalized.2. If there is a 2nd letter it is always lower case.

DMITRI MENDELEEV: Russian.-Developed a table based on atomic mass-Elements placed in vertical columns-If an element’s properties didn’t fit in column, he left a space.

What do you think these blanks squares represented?

HENRY MOSELEY: (1912)-used x-rays to determine atomic # and used it to refine the p. table

PERIODIC LAW:

The law governing the periodic table. Mendeleev stated, “When elements are listed in order of increasing atomic #, elements with similar properties recur at regular intervals.”

PERIODIC TABLE ARRANGEMENT:

Period: horizontal rows on the table numbered 1-7. **PERIOD # TELLS YOU HOW MANY ORBITS TO DRAW**

Family or group: vertical column on table. A group contains elements with similar properties. Roman numerals show the families. **GROUP # TELLS YOU HOW MANY VALENCE ELECTRONS YOU HAVE**

Because of the change in their conductivity they are referred to as semiconductors and they serve as the basis of computer

chips.

THREE MAJOR DIVISIONS OF PERIODIC TABLE:

(There is a staircase like ladder running down right side of table)

-Elements on left are metals.-Elements on right are non-metals-Elements immediately adjacent to the line dividing metals and non-metals are metalloids (except for aluminum that is a metal).

METALS: ELEMENTS ON LEFT SIDE OF THE PERIODIC TABLE.

Usual Characteristics: 1. form + ions by giving up electrons.2. be malleable - able to bend or be hammered without breaking3. be ductile- able to stretch into wire4. be solid at room temp (except for mercury)5. have luster - they are shiny6. conduct electricity and heat7. silver colored (except for gold and copper)8. react with acids9. react with non-metals10. they do not react with each other

METALLOIDS: ELEMENTS ADJACENT TO THE STAIR CASE LIKE LINE BETWEEN METALS AND NONMETALS.

Metalloids have characteristics of both metals and non-metals.

Characteristics:1. solid at room temp.2. Poor conductors of electricity at low temperature3. Good conductors of electricity at high temperatures

NONMETALS: ELEMENTS ON RIGHT SIDE OF THE PERIODIC TABLE. (NOT INCLUDING COLUMN 18 – THE NOBLE GASES).

Characteristics:1. Form negative ions2. React with metals3. Brittle4. Dull in appearance5. Poor conductors of heat and electricity6. Do not react with acids7. React with each other

FOUR FAMILIES (GROUPS) YOU SHOULD KNOW!

Alkali metals- Group IA Alkaline Earth Metals- Group IIA Halogens- Group VIIB Noble gases- (inert gases). Group O.

ALKALI METALS: FIRST COLUMN ON THE PERIODIC TABLE.

Characteristics:1. Metals2. Very soft (can be cut with a butter knife) 3. One electron in outer most energy level (they form +1 ions by losing this

electron).4. Low Ionization Energy and Electronegativity making it easy to remove

electrons.5. Highly reactive (react violently with water, acids and peroxides)6. Reactivity increases going down the family.7. Form very strong bonds.

ALKALINE EARTH METALS : SECOND COLUMN ON PERIODIC TABLE.

Characteristics:1. Metals2. Two electrons in outer shell (form +2 ions by losing both electrons)3. Ionization energy and electronegativity slightly higher than the alkali metals4. A little less reactive than alkali metals5. Reactivity increases down the family6. Form slightly weaker bonds than the alkali metals.7. Slightly harder than the alkali metals

HALOGENS: NEXT TO LAST COLUMN ON PERIODIC TABLE.

Characteristics:1. Non-metals 2. Seven electrons in outer energy level (gain 1 electron to

become –1 ions) 3. very high ionization energy and electronegativity making

it easier for them to gain electrons.4. Highly reactive5. Reactivity increases going up the family6. React with all elements on the periodic table except Helium, Neon and Argon7. Do not occur as individual (unbonded atoms) in nature

Halogens will form a “diatomic molecule” – a molecule made up of 2 atoms of the same element.There are seven elements that will form diatomic molecules any time they are present in their pure form. These elements are:

Hydrogen (H2) Nitrogen (N2) Oxygen (O2) Fluorine (F2) Chorine(Cl2) Bromine(Br2) Iodine(I2)

Remember them with: “Harry’s brother Ike found no candy outside.”

NOBLE GASES: LAST COLUMN ON PERIODIC TABLE

Noble gases have complete outer energy levels (8 e- in their outer energy level, except Helium which has 2e- in its only energy level, remember the 1st energy level is filled with 2 e -). They wont mix with other elements easily because they’re energy levels are complete. That’s why their “Nobel” gasses- they don’t mix with “common” elements.

Characteristics:1. Stable electron arrangement (the outer energy level is filled)2. Extremely high Ionization Energy3. Tend not to form ions 4. Inert - tend not to take part in chemical changes5. Very low melting points and boiling points making them gases at room temperature.

SOME REVIEW:

Transition elements: or the d-block. We will not be using these in class. These elements have suborbitals that act like valence electrons and are hard to determine behavior

Most likely groups to give up electrons?Metals because they have a lower group #, it is easier to give up a few than gain a lot Most likely to gain/grab electrons?Non-metals because they are close to 8 (a full valence shell). It is easier to get a few than give up a lot.

If an element gains an electron it becomes negative, if it loses one it becomes positively charged.

When you turn on a light for example, you are exciting the electrons in the filament by sending an electric current through the wire. The activity of the electrons moving from shell to shell causes a release in energy seen as light and felt as heat as the electrons fall back to their positions.

PERIODIC TABLE PUNS #1

Use your imagination and the elements in the Periodic Table to solve each pun!

Example: Five cents - Nickel Ni

1. What you do in a play _________________________ __________

2. What you do to a wrinkled shirt _________________________ __________

3. “Tasty” part of your mouth _________________________ __________

4. Someone who likes to start fires _________________________ __________

5. Superman’s weakness _________________________ __________

6. Your brother or mine _________________________ __________

7. Extinct _________________________ __________

8. Imitation diamond _________________________ __________

9. A type of flower _________________________ __________

10. Las Vegas lights _________________________ __________

11. Police _________________________ __________

12. Golden State _________________________ __________

13. Name of a goofy convict _________________________ __________

14. Mr. Mony's enemy _________________________ __________

15. What you do to flowers _________________________ __________

16. What you did to ripped jeans _________________________ __________

17. A “prize” element _________________________ __________

18. A very smart person _________________________ __________

19. Person from the big blue planet _________________________ __________

20. A fur seller _________________________ __________

PERIODIC TABLE PUNS #2

Use your imagination and the elements in the Periodic Table to solve each pun!

1. Not an exciting person _________________________ __________

2. Thanksgiving guests _________________________ __________

3. Get clean with this _________________________ __________

4. Drive away in style in a ____ _________________________ __________

5. Does a body good _________________________ __________

6. Proud to be an _____ _________________________ __________

7. Mickey’s pal _________________________ __________

8. Warrior Princess _________________________ __________

9. A nice guy _________________________ __________

10. Someone who loves computers _________________________ __________

11. The first person in a race has the ___ _________________________ __________

12. E = mc2 _________________________ __________

13. This man followed the yellow brick road _________________________ __________

14. How to tell a secret _________________________ __________

15. Monday night TV show _________________________ __________

16. A phrase from Dr. Suess _________________________ __________

17. What a doctor does to his patients _________________________ __________

18. Part of a whole _________________________ __________

19. Place for washing dishes _________________________ __________

20. Drink in an Al can _________________________ __________

21. Happens when you lasso a horse _________________________ __________

22. What a dog does with a bone _________________________ __________

23. A sinking ship _________________________ __________

24. What a cloud does _________________________ __________

ELECTRON DOT MODELS (LEWIS STRUCTURES)Def - A simple model of the atom that can be used to illustrate chemical bondingElectron dot models consist of the Chemical symbol of the element surrounded by the valence electrons.Example: Sodium

The Bohr-Rutherford model for sodium is:

This atom has only one valence electron so the electron dot model would be

Rules:1. No more than 2 electron dots per side2. Do not pair electron dots until there is one dot per side

TRY THESE!

Draw Lewis Dot structures around the elements. Remember to ONLY draw the electrons in the outer shell.

H He

Li Be B C N O F Ne

Na Mg Al Si P S Cl Ar

K Ca Ga Ge As Se Br Kr

IONIC AND COVALENT BONDINGIONIC BONDS

Ionic Bond: a chemical bond due to the transfer of electrons between a metal and a non-metal and their resulting attractions.

For example, common table salt is sodium chloride. When sodium (Na) and chlorine (Cl) are combined, the sodium atoms each lose an electron, (Na+), and the chlorine atoms each gain an electron (Cl−). These ions are then attracted to each other in a 1:1 ratio to form sodium chloride (NaCl).

Na + Cl → Na+ + Cl− → NaCl

COVALENT BONDS

Covalent Bond: a chemical bond due to a sharing of electrons between two non-metals. OR a non-metal and hydrogen.

Neither atom wants to give up its electrons to the other, so they share. The shared electrons stay between them, forming a very strong bond. They can share one, two, or three electrons forming single, double, or triple bonds. They can also share electrons between more than 2 atoms.

Examples: F2 (this is two flourine atoms in a covalent bond) H2O (two hydrogen atoms with one oxygen atom)

CH4 (this is carbon and 4 hydrogens)

Diatomic molecules are covalently bonded: List the seven diatomic molecules here:

IONIC AND COVALENT COMPOUNDS

Ionic Compounds Covalent Compounds

Made up of ions created by a transfer of electrons from a metal to a nonmetal

Crystalline solid

Formula indicates the ratio between the ions in the crystal.

High overall attractions (all + ions attract all - ions; all - ions attract all + ions) resulting in high mp and bp and low volatility (all are solids at room temperature)

Tend to be water soluble

Electrolytes - substances that conduct electricity in solution (due to the presence of free ions)

Made up of molecules created by the sharing of electrons by nonmetals.

Molecular compounds.

Formula indicates the actual number of atoms of each element in each molecule

Strong attractions between atoms within a molecule (due to overlap of valence orbits), but low attraction between molecules resulting in low mp and bp and high volatility (most are liquids or gases at room temperature)

Tend to be alcohol soluble

Nonelectrolytes - Substances that do not conduct electricity in solution (no free ions)

ELECTRON DOT MODELS AND BONDING

Determine the formulas for the compounds formed by the following pairs of elements by drawing electron dot models showing the electron transfers.

1) Lithium (1 dot) + Bromine (7 dots)

2) Hydrogen (2 dots) + Oxygen (6 dots)

3) Hafnium (4 dots) + Oxygen (6 dots)

4) Scandium (3 dots) + Sulfur (6 dots)

5) Sodium (1 dot) + Chloride (7 dots)

6) Technetium (7 dots) + Iodine (7 dots)

7) Zinc (2 dots) + Phosphorus (5 dots)

CHEMICAL REACTIONS

LAW OF CONSERVATION OF MASS

ACIDS, BASES, AND SALTS:ACIDS

Acids are compounds that releases H+1 ions in solution

Characteristics of acids:1. Sour taste like lemon juice2. Water Soluble3. Electrolytes- substances that conduct electricity when in solution due

to free ions4. React with metals to release H2 gas5. React with carbonates to form a salt6. React with metal and causes oxidation7. React with bases to form a salt and water (this is called neutralization)8. Changes litmus paper red9. pH less than 7.0

BASES

Bases are substances that release OH- (hydroxide ions) in solution

Characteristics of bases:1. Bitter taste2. Water Soluble3. Slippery to touch (i.e. soap)4. Emulsify fats and oils (break into drops and hold suspended in

solution)5. Electrolytes6. React with non-metal and causes oxidation7. React with calcium and magnesium compounds8. React with acids (neutralization)9. Changes litmus paper blue10. pH greater than 7.0

SALTS

Salts are compounds containing a metallic ion (+ ion) and an acid-radical ion (-ion)(Metallic ion is any + ion other than H+; Acid-radical ion is any –ion other than OH-)

Characteristics of salts:1. Water Soluble2. Salty taste3. Solid at room temperature4. High melting point5. Electrolytes

Common Acids:Hydrochloric Acid (HCl)

Sulfuric Acid (H2SO4 )Lemon Juice (Citric Acid)

Nitric Acid (HNO3)Vinegar (Acetic Acid)

Common Bases:Sodium Hydroxide (NaOH)

Potassium Hydroxide (KOH)Ammonium Hydroxide (NH4OH)

Calcium Hydroxide (Ca(OH)2)Magnesium Hydroxide (Mg(OH)2)

6. pH around 7.0

INDICATORS

Indicators are chemicals that change color in the presence of H+ or OH- ions.

Indicators can be used to tell:a. If a substance is an acid or baseb. Strength of an acid or base

Common indicators: Litmus paper: red in acid, blue in base Phenolphtalein: colorless in acid, pink in base Hydrine paper: color varies depending upon the strength of the acid or base

PH SCALE

Acid/base strength is measured on a scale called the ph scale. pH stands for “ % of H+”

←Acid Base→│-------------------------│-------------------------│0 7.0 14

Neutral

Strength increases moving away from 7.0

REVIEW QUESTIONS(D10)(PCAPT)Which substance cannot be decomposed into simpler substances?

A. AmmoniaB. AluminumC. MethaneD. Methanol

(D6) A positively charged particle will:A. repel a negatively charged particleB. attract a negatively charged particleC. attract a positively charged D. run in fear from a neutral particle

(D10)(PCAPT)The chemical properties of an element are determined by its

A. Atomic massB. Proton numberC. Electron arrangementD. Atomic size

D10)(PCAPT) Oxygen has an atomic number of 8. Which of the following elements would you expect to be MOST similar to oxygen in terms of its chemical properties?

A. Nitrogen (N)B. Fluorine (f)C. Sulfur (S)D. Chlorine (Cl)

(D10) In order for an atom to be neutral the:A. number of protons = the number of electronsB. number of protons = the number of neutronsC. number of electrons = the number of neutronsD. number of protons > than the number of

electrons

(D10) Atom A has 5 protons and 5 neutrons; atom B has 5 protons and 6 neutrons. The atoms are:

A. isotopes of the same element.B. atoms of different elements.C. different sizesD. different in their properties

(D10)(PCAPT)What do the elements carbon, silicon, germanium and tin have in common?

A. They are metalsB. They are in the same periodC. They have the same number of electronsD. They have four electrons in their outer shell

For the next 3 questions refer to the drawing below.

(D10) The mass number of this same atom is:A) 6 B) 16 C) 17 D) 33

(D10) This atom would have ____ valence electrons.A) 4 B) 5 C) 6 D) 7

(D10) If another isotope of this element existed with a Mass Number of 30, it would differ from the one shown in the number of which particle?

A. protonsB. neutronsC. electronsD. all of the above

(D10) The maximum number of electrons in the outer orbit of any atom is:A) 2 B) 8 C) 10 D) 14

(D10)(PCAPT)Nitrogen has an atomic number of 7 and an atomic mass of 14.01. Which of the following is most true of nitrogen?

A. Each atom of nitrogen has 7 protons and 7 neutrons

B. Each atom of nitrogen has 7 protons and 14 neutrons

C. Each atom of nitrogen has 14 protons and 14 neutrons

D. Each atom of nitrogen has 7 protons and 14 neutrons

(D10)(PCAPT) The atomic number of iron is 26, and the atomic mass is 55.847. What do these numbers mean in regard to protons, electrons and neutrons?

A. There are 26 each of protons and neutrons, and the rest of the mass is the result of electrons.

B. There are 26 protons and 26 electrons. Some atoms of iron have 29 neutrons; the 0.847 shows that there is more than one isotope of iron.

C. There are 26 protons and 29 neutrons. Each particle has an atomic mass of 1.

D. There are 26 protons and 26 neutrons. Since neutrons have slightly more mass than protons, the mass is greater than 52.

For the next 3 questions refer to the symbol drawn below.

(D10) What is the mass number of the atom represented by this symbol?A) 92 B) 146 C) 238 D) 330

(D10) What is the atomic number of this atom?A) 92 B) 146 C) 238 D) 330

(D10) This symbol is referred to as a(n):A. Formula SymbolB. Isotopic SymbolC. Atomic SymbolD. Ionic Symbol

(D10) In the drawing to the right, the atoms all belong to what family?

A. Nobel GassesB. Alkaline EarthC. HalogenD. Alkaline Metals

(D10) In order to be identified as the element carbon (C), an atom must have ______.

A. 6 protonsB. 6 neutronsC. 12 electronsD. 12 electrons

(D10) Oxygen has an atomic number of 8. Which of the following elements would you expect to be most similar to oxygen in terms of its chemical properties?

A. Nitrogen (N)B. Fluorine (F)C. Sulfur (S)D. Chlorine (Cl)

(D10) Group I (the alkali metals) includes lithium (Li), sodium (Na), and potassium (K). These elements have similar chemical properties because they have the same __________.

A. numbers of protons and neutronsB. numbers of electrons in the outer energy levelC. numbers of protons in the nucleusD. numbers of neutrons in the nucleus

(D10) Metals and nonmetals generally form ionic bonds with each other. Which of the following sets of elements will most likely for an ionic bond?

A. Na, FB. Cl, FC. Na, KD. He, O

(D10) The chemical properties of an element are determined by its

A. atomic mass.B. proton number.C. electron arrangement.D. atomic size.

(D10) Study the table below. Which atom has a net positive charge?

A. Atom WB. Atom XC. Atom YD. Atom Z

(D10) Which element in the table above has the highest atomic mass?

A. Atom WB. Atom XC. Atom YD. Atom Z

(D10) Which of the following is the most important factor in determining an element’s place in the periodic table?

A. number of protonsB. number of neutronsC. atomic chargeD. atomic density

(D10). Elements in the same family all have the same:A. Atomic NumbersB. number of valence electronsC. valence energy levelD. number of protons

(D10) On the Periodic Table the elements are arranged by:

A. Atomic Number

B. Mass NumberC. number of neutronsD. number of isotopes

(D10) An element that shows characteristics of both metals and nonmetals is:

A. an alkaline earth metal.B. a noble gasC. a metalloid.D. a halogen.

(D10) An element conducts electricity and heat, and has high luster. It is probably a:

A. MetalB. NonmetalC. LiquidD. Gas

(D10)(PCAPT) The mass of an element is determined mainly by its

A. Atomic numberB. Number of protons and neutronsC. Electron arrangementD. Atomic size

(D11) Which of the following is best classified as a compound?

A. Helium (He), because it contains only one type of atom

B. Oxygen ( O2 ), because it contains two of the same type of atoms

C. Carbon dioxide (CO2), because it contains two different types of atoms

D. Manganese (Mn), because it contains a metal and a nonmetal

(D11) In general, the force that holds atoms together in a compound is called

A. gravityB. magnetismC. chemical bondD. electronegativity

(D11) The formation of a chemical bond involvesA. only the protonsB. electrons & neutronsC. protons & electrons

D. only the electrons

(D11) When an atom becomes an ion it is attempting to:

A. gain electronsB. lose electronsC. share electronsD. obtain a complete valence energy level

(D11) To become a +3 ion, an atom must:A. gain 3 electronsB. lose 3 electronsC. gain 3 protonsD. lose 3 protons

(D11) The chemical properties of elements are determined by the gain, loss, or sharing of:

A. electronsB. ionsC. protonsD. neutrons

(D11) A covalent bond would most likely be formed between Fluorine and:

A. SodiumB. OxygenC. MagnesiumD. Helium

(D11) A bond due to a transfer of electrons from a metal to a nonmetal is a(an):

A. physical bondB. ionic bondC. covalent bondD. metallic bond

(D11) An ionic compound forms between aA. metal & nonmetal

B. nonmetal and nonmetalC. metalloid and nonmetal

D. metal & metal

(D11) An atom gains two electrons to have a ___ charge.A. +2B. +4C. -2D. 0

(D11) Two atoms that are sharing a pair of electrons have formed a(n) _______ bond.

A. IonicB. JamesC. Covalent

D. Cooperative

(D11)(PCAPT)When a metal atom combines with a nonmetal atom, the nonmetal atom will

A. Lose electrons B. Share electrons C. Grain electrons D. Not change its number of electrons

(D11)(PCAPT)A balanced chemical equation reflects the idea that the mass of the products

A. is greater than the mass of the reactantsB. Is less than the mass of the reactantsC. Equals the mass of the reactantsD. Is not related to the mass of the reactants

(D11) In a simple chemical compound the total charge must add up to:

A. an even numberB. zeroC. an odd numberD. eight

(D12) Which of the following has the most H+ ions present?

A. strong acidB. weak acidC. strong baseD. weak base

(D12) An acid's properties are due to the presence of:A. Na+ ionsB. OH- ionsC. H+ ionsD. Cl- ions

(D12) A base is a compound that contains:A. CO3

2- ionsB. OH- ionsC. H+ ionsD. O2- ions

(D12) A material, such as Cabbage Juice, that changes color in an acid, or base is called a(n):

A. chameleonB. acidC. baseD. indicator

(D12) pH scale ranges from 0 to:A. 7B. 10C. 14

D. 20

(D12) The pH that indicates the strongest acid is:A. 0.6B. 6.3C. 7.0D. 10.5

(D12) Which of the following has the most OH- ions present?

A. strong acidB. weak acidC. strong baseD. weak base

(D12) The pH of a salt is around:A. 1.4B. 7.0C. 10.2D. 14.0

(D12) When an acid and base react, the resulting solution has a pH around:

A. 1.0B. 6.0C. 7.0D. 12.0

(D12) The safest way to test for an acid or base is:A. see how it reactsB. tasting itC. touching itD. using an indicator

HCl + NaHCO3 → NaCl + CO2 + H2O

(D12) Antacids contain bases that react with the acid in your stomach to relieve indigestion. In the reaction above, NaHCO3 reacts with the strong hydrochloric acid, HCl, to form a salt, carbon dioxide, and water. This type of reaction is called

A. dehydration B. oxidation C. titrationD. neutralization

(D12) Determine if the following are acids, bases or neutral. If the compound is an acid or base indicate if it is weak or strong.

Solution A has a pH of 11.4 ________________________

Solution B has a pH of 6.3 _________________________

Solution C has a pH of 4.3 ________________________

Solution D has a pH of 7.0 ________________________

Solution E has a pH of 8.2 _________________________

(D12)(PCAPT) When an acid and a base react with each other __________and ___________are produced.

A. Salt and CO2

B. Hydrogen and heatC. Salt and waterD. Heat and oxygen

(D12) One property of bases is that they:A. are nonelectrolytesB. react with metals to produce Hydrogen gasC. taste bitterD. turn litmus red

(D12) A compound contains a metal and a nonmetal. The compound would be a(n):

A. saltB. covalent compoundC. acidD. base

(D12) One property of salts is that they taste:A. saltyB. sweetC. sourD. bitter

(D12) An indicator determines the presence of an acid, or a base by:

A. producing bubblesB. giving off an odorC. changing colorD. burning brightly

Which of the following is an example of a chemical reaction?

A. Aluminum foil being cut into smaller piecesB. A drop of food coloring dissolving in waterC. Melted butter becoming a solid when placed in

the refrigeratorD. The surface of a copper penny changing color

after being in a drawer for years

Which of the following ALWAYS results from a chemical reaction?

A. FireB. BubblesC. A new substance that is a solidD. A new substance that can be a solid, liquid, or gas

A student placed a liquid in a jar and sealed it. Then she heated the liquid and it turned into a gas. If the number of atoms in the sealed jar stayed the same, what happened to the mass of the jar and everything inside it after she heated it?

A. The mass increased.B. The mass decreased.C. The mass stayed the same.D. It depends on whether a chemical reaction

occurred.

A student places some baking soda and a jar of lemon juice in a plastic bag and seals the bag. She weighs the bag and everything in it. She shakes the bag so that the lemon juice spills out of the jar and mixes with the baking soda inside the bag. The student observes that bubbles form and the bag expands.

If the student weighs the bag and everything in it after the bubbling stops and compares the final weight to the starting weight, what will she find out?

A. The final weight will be greater than the starting weight because new atoms are produced during the experiment.

B. The final weight will be less than the starting weight because some of the atoms are destroyed during the experiment.

C. The final weight will be the same as the starting weight because the number of each kind of atom does not change during the experiment.

D. The final weight will be the same as the starting weight because some atoms are destroyed, but new ones are created during the experiment.

A student adds water and sugar to a jar and seals the jar so that nothing can get in or out. The student then weighs the jar containing the water and sugar. After some sugar dissolves, the student weighs the jar and its contents again.

What will happen to the weight of the jar containing the water and sugar after some of the sugar dissolves?

A. The weight will stay the same.B. The weight will increase.C. The weight will decrease.D. The weight will depend on how much sugar

dissolves.

In the diagrams below, sulfur atoms are represented by gray circles, carbon atoms are represented by black circles, and oxygen atoms are represented by white circles.Which of the following could be a product of the chemical reaction between sulfur and oxygen?

A.

B.

C.

D.

Which of the following could represent a chemical reaction?Atoms are represented by circles, and molecules are represented by circles that are connected to each other. The different colored circles represent different kinds of atoms.

A.

B.

C.

D.

Using the information about the five liquids in the table below, which of the following liquids could be the same substance?

Volume

(mL)Flammabl

eBoiling Point

(°C)Color

Liquid 1 25 no 100 colorless


Liquid 3 25 yes 100 colorless


Liquid 5 25 no 100 yellow

A. Liquids 1 and 2B. Liquids 1 and 3C. Liquids 1 and 4D. Liquids 1 and 5

Which of the following is an example of a chemical reaction?

A. Water evaporating from a pot on a hot stoveB. Sand being removed from sea water by filtration

C. A spoonful of sugar dissolving in a glass of waterD. A white solid forming when two clear liquids are

poured together

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