~ 1 ~

Topic 2: Atomic Structure Regents Chemistry

Mr. Mancuso

The Element Song Tom Lehrer There’s antimony, arsenic, aluminum, selenium And hydrogen and oxygen and nitrogen and rhenium, And nickel, neodymium, neptunium, germanium, And iron, americium, ruthenium, uranium, Europium, zirconium, lutetium, vanadium, And lanthanum, and osmium and astatine and radium, And gold and protactinium and indium and gallium, And iodine and thorium and thulium and thallium. There’s yttrium, ytterbium, actinium, rubidium, And boron, gadolinium, niobium, iridium, And strontium, and silicon and silver and samarium, And bismuth, bromine, lithium, beryllium, and barium. There’s holmium and helium and hafnium and erbium, And phosphorus and francium and fluorine and terbium, And manganese and mercury, molybdenum, magnesium, Dysprosium and scandium and cerium and cesium, And lead, praseodymium, and platinum, plutonium, Palladium, promethium, potassium, polonium, And tantalum, technetium, titanium, tellurium, And cadmium and calcium and chromium and curium. There’s sulfur, californium, and fermium, berkelium, And also mendelevium, einsteinium, nobelium, And argon, krypton, neon, radon, xenon, zinc, and rhodium, And chlorine, carbon, cobalt, copper, tungsten, tin, and sodium. These are the only ones of which the news has come to Ha’vard, And there may be many others, but they haven’t been discavard.

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Symbol Name Meaning Uses

H

G: hydro genes water former Most abundant element

He

G: helios the sun Balloons

Li

G: lithos stone Batteries, Lubricants

Be

G: beryllos mineral Spacecraft, Missiles

B

Arabic: bawroq white, borax Heat resistant alloys

C

L: carbo coal All living things

N

L: nitro / gen native soda / born Most of the atmosphere

O

G: oxys / gen sharp / born Supports life

F

L: fluere flow Toothpaste, refrigerants

Ne

G: neos new Lights

Na

L: natrium Medicine, agriculture

Mg

L: magnes magnet Airplanes, Missiles

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Al

L: alumen substance with astringent taste Soda cans

Si

L silex flint Glass, Surgeries

P

G: phosphoros light bringer Fertilizers, Detergents

S

L: sulphur Matches, Gunpowder

Cl

G: chloros grass green Water purification, Bleaches

Ar

G: argos inactive Lighting

K

L: kalium Soap, Glass

Ca

L: calcis lime Bones and Shells

Ti

Greek Mythology: titans Golf Clubs

Cr

G: chroma color Gives rubies their red color

Mn

Bones

Fe

L: ferrum Basic ingredient of steel

Co

G: kobolos a goblin Alloy that helps form jet propulsion

engines

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Ni

German: kupfernickel false copper Coins

Cu

L: cuprum (w/ zinc = brass) (w/ tin = bronze) it

and Au are only colored metals

Zn

German: zink, akin to zinn, tin Coating metal for batteries

As

G: arsenikon valiant Poison

Br

G: bromos stench Disinfectants and Sedatives

Kr

G: kryptos hidden Radioactive gas (Planet of

Superman’s Origin)

Rb

Zr

Named for the mineral zircon Nuclear reactors and Rockets

Pd

English: planetoid Pallas discovered 1801 Surgical Instruments

Ag

L: argentums Best conductor of heat and

electricity

Cd

L: cadmia, calamine, a zinc ore Batteries

Sn

L: stannum Cans, does not rust

Sb

Batteries

~ 5 ~

I

G: iodes produces a violet spectrum line

“Iodized salt” prevent thyroid

problems

Xe

G: xenos strange High speed flash bulbs

Cs

Ba

G: barys heavy Used for x-rays, people drink it

La

W

German: wolfram heavy stone Light bulbs, used in light bulbs

Pt

Spanish: plata silver Jewelry, more precious than gold

Au

L: aurum Currency, malleable, colored metal

Hg

L: hydrarygus liquid silver Thermometers, metal liquid

Pb

L: plumbum Plumbing, Pipes

Bi

German: bisemutum white mass Electric fuses

Rn

L: comes from radium Radiation, cancer therapy

(Heaviest gas)

Fr

~ 6 ~

Ra

L: radius ray

U

English: planet Uranus Nuclear reactors, Heaviest natural element

Np

English: planet Neptune

Pu

English: planet Pluto Nuclear weapons

Structure of the Atom Early ideas about matter: (PreHistory ~1000 c.e.)

• Earth, wind, fire, and water

• 400 BC Democritus, a Greek philosopher considered matter to be made of small, indivisible pieces, called it atomos (“individible”)

• Ideas opposed by Aristotle and Socrates, who argued that matter is continuous, and infinitely

divisible (there is no smallest piece)

Middle Ages ~ 1800

• Alchemy Search to turn non-valuable metals into gold

• “Magic”; potions, fireworks, gunpowder

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First Meaningful Atomic Theory (~1805)

• 1803-1807 John Dalton (English school teacher) proposed first meaningful atomic theory:

• __________________________________________________________________

__________________________________________________________________ __________________________________________________________________

• __________________________________________________________________ __________________________________________________________________ __________________________________________________________________

• __________________________________________________________________ __________________________________________________________________ __________________________________________________________________

Law of Constant Compositions:

__________________________________________________________________ __________________________________________________________________ __________________________________________________________________

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Developments Leading to Modern Atomic Theory (Dalton Present):

• 1897 J.J. Thompson (British physicist) discovered electrons and protons

o Plum pudding model – evenly distributed electrons within a positive matrix

Positive matrix

o Each electron has a mass of: __________________________________________ ____________________________________________________________ ____________________________________________________________

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• 1911 Ernest Rutherford’s gold foil experiment

Rutherford’s Conclusions (Postulates):

(1) ___________________________________________________________ ___________________________________________________________

(2) _____________________________________________________________ _____________________________________________________________ _____________________________________________________________

• 1932 James Chadwick (British scientist) discovered neutrons

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The Modern Atomic Theory: In the modern theory

• _______________________________________________________________ _______________________________________________________________ _______________________________________________________________

• _______________________________________________________________

_______________________________________________________________ _______________________________________________________________

• _______________________________________________________________ _______________________________________________________________ _______________________________________________________________

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The Major Nucleons

Protons:

• _______________________________________________________________

• _______________________________________________________________

• _______________________________________________________________ _______________________________________________________________

• _______________________________________________________________ _______________________________________________________________

Neutrons: • _____________________________________________________________________

• _____________________________________________________________________

The addition of an atom’s protons and neutrons is it’s _____________________________________

Electrons are NOT nucleons, although they do play a significant role in the behavior of individual atoms

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Ions: ________________________________________________________________ ________________________________________________________________ ________________________________________________________________ isotopes: ________________________________________________________________ ________________________________________________________________ ________________________________________________________________

Some of the Isotopes of Carbon Symbol Number of protons Number of electrons Number of neutrons Name

11C 6 6 5 Carbon-11 12C 6 6 6 Carbon-12 13C 6 6 7 Carbon-13 14C 6 6 8 Carbon-14

*Almost 99% of the carbon found in nature consists of 12C **In a natural sample of hydrogen, about one atom in every 6000 is an atom of Hydrogen-2 (2H or deuterium) This structure can be written as part of a chemical symbol.

Example:

3

715 + N

Mass Number Atomic Number Charge

7 protons 8 neutrons (15 – 7)

4 electrons

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Guided Practice 1. Write the chemical symbol for the ion with 12 protons and 10 electrons. 2. Write the chemical symbol for the isotope with 30 protons, 30 electrons, and 35 neutrons

3. How many protons, neutrons, and electrons are present in the +2

Ni 2859

ion?

4. Write the chemical symbol for the isotope with 20 protons, 18 electrons, and 25 neutrons

5. How many protons, neutrons, and electrons are present in the +3

Ce 58

140 ion?

6. How many protons, neutrons, and electrons are present in the -4

C 13

ion?

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Student Practice 1. Write the chemical symbol for the ions with 74 protons and 68 electrons. 2. Write the chemical symbol for the ion with 95 protons and 89 electrons. 3. Write the chemical symbol for the ion with 33 protons and 36 electrons. . 4. Write the chemical symbol for the isotope with 88 protons, 91 electrons, and 88 neutrons. 5. Write the chemical symbol for the isotope with 54 protons, 53 electrons, and 91 neutrons.

6. How many protons, neutrons, and electrons are present in the +4

Zr 4091

ion?

7. How many protons, neutrons, and electrons are present in the -2

Se 79

ion?

8. How many protons, neutrons, and electrons are present in the -3

Sc 2145

ion?

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Isotopes and Average Atomic Mass

• The average atomic mass is the weighted average of all the naturally occurring isotopes of an element.

Guided Practice

1. A sample of cesium is 75% 133Cs, 20% 132Cs, and 5% 134Cs. What is the average atomic mass?

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Student Practice Determine the average atomic mass of the following mixtures isotopes. Show all work.

1. 80% 127 I, 17% 126 I, and 3% 128 I

___________________

2. 50% 197 Au, 50% 198 Au

___________________

3. 15% 55 Fe, 85% 56 Fe

___________________

4. 99% 1 H, 0.8% 2H, 0.2% 3H

___________________

5. 95% 14 N, 3% 15 N, 2% 16 N

___________________

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Complete the following chart for each specific species: Element / Ion Atomic Number Atomic Mass Most Common Isotope Protons Neutrons Electrons

H

H+

C

612

+ Li

37

− Cl

1735

+2

Mg 1224

75 As 3-

108 Ag

108 Ag +1

32 S -2

U - 238

95 Zr +4

120 Sn

Radon - 222

Iodine - 133

Carbon - 14

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Electrons

• Electrons surround the nucleus of an atom in an electron cloud

• Heisenberg Uncertainty Principle: ___________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________

• Energy (Quantum) Levels

o 1913 Neils Bohr (Danish physicist); Bohr model

o ________________________________________________________________________

o The first shell (n=1) can hold _________________________________________________

o The outermost shell ________________________________________________________

________________________________________________________________________ ________________________________________________________________________

________________________________________________________________________

o Group numbers ___________________________________________________________ ________________________________________________________________________

o Nobel gases _____________________________________________________________ _______________________________________________________________________

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Electron Configuration

• Electrons occupy energy levels (energy shells)

o Each shell is numbered (quantum number)

• n = 1 (closest to the nucleus) • n = 2 • n = 3 • up to n = 7 (farthest from nucleus)

• Ground state ___________________________________________________________________

___________________________________________________________________

o In the ground state, the electrons will occupy the _________________________________ ________________________________________________________________________

• Excited state __________________________________________________________________

___________________________________________________________________ ___________________________________________________________________

• When electrons fall to lower energy levels they emit radiation in the form of:

o _______________________________ and ____________________________________

Electron Configuration:

2 - 8 - 18 - 18 - 3

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• Each energy level can be divided into sublevels. The sublevels do not fill in the “expected order” and account for why some higher energy levels begin filling before the lower ones.

Electrons per sublevel:

Electrons per period:

n1 =

n2 =

n3 =

n4 =

n5 =

n6 =

n7 =

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Spectral Lines

Visible spectrum

400 nm 550 nm 700 nm

nm = __________________________________

400 nm

700 nm Unknown sample (star)

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Lewis Dot Diagrams Draw Lewis dot diagrams for the following atoms. Identify its ground state electron configuration, as well as a possible excited state configuration. 1. calcium

2. carbon

3. potassium

4. helium 5. argon 6. oxygen

7. aluminum 8. phosphorus 9. bromine

10. hydrogen 11. copper 12. gold

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Draw Lewis dot diagrams for the following ions, and identify how many total electrons each species has. 1. calcium +1 2. carbon -3 3. potassium -5

4. helium +1 5. argon +4 6. oxygen +1

7. aluminum -5 8. phosphorus -2 9. bromine -4

10. hydrogen 0 11. copper -2 12. gold +3

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Application of Atomic Mass Samples of an unknown element X were collected and their masses were recorded. Use the information Presented in the data table to answer the following questions.

Isotope Mass (amu) Percent Abundance 1

38

9.67

2

39

78.68

3

40

11.34

4

41

0.31

1. What is the most common isotope of element X? __________________________

2. Calculate the average atomic mass of element X. Show your work below

__________________________

3. Use your periodic table to identify element X based on its average atomic mass._______________ 5. What is the atomic number of this element? __________________________ 6. Draw a Lewis-dot diagram of this element.

6. This atom forms an ion with a charge of 1+. a. Write the chemical symbol for the ion of this element, using the mass number for the most

common isotope and it’s atomic number.

b. How many protons, neutrons, and electrons are present in your answer?

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The Periodic Table

The horizontal rows

• are called: ________________________

o The number of each period indicates _________________________________ _______________________________________________________________

o From left to right, the number of valence electrons increases

The vertical columns

• are called: ______________________ or ____________________________.

• Groups are designated by the numbers 1-18

o The elements in a group have _____________________________________ _____________________________________________________________

At the bottom of the table are two series, the _________________ and __________________ series, which make up the f-block.

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Groups of Elements:

• Each group has characteristic properties that are directly related to electron configuration

• In going from top to bottom of any group, each element has one more occupied energy level (quantum level) than the element above it. Otherwise the electron structures are similar.

o Group 1 - _______________________________________________ ________________________________________________________________

o Group 2 – ________________________________________________ ________________________________________________________________

________________________________________________________________ ________________________________________________________________

• ________________________________________________________________

________________________________________________________________

o Groups 3 through 12 – _____________________________________________________ The presence of a transition element in a compound _______________________

_________________________________________________________________

o Group 16 - ________________________________________________ _________________________________________________________________

_________________________________________________________________

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o Group 17 – ________________________________________________ ___________________________________

Fluorine and Chlorine are ______________________________

Bromine is __________________________________________

Iodine and Astatine are ________________________________

___________________________________________________

__________________________________________________________

__________________________________________________________

Fluorine is _________________________________________________

o Group 18 – __________________________________________________ Contain a full _______________________________________

Mostly ___________________________________________

Reference Table “S”

First Ionization Energy – (kJ / mol)_________________________________________________ ______________________________________________________________________________ ______________________________________________________________________________ Electronegativity – (scale 0.8 – 4.0)__________________________________________________ _______________________________________________________________________________ _______________________________________________________________________________

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Atomic Radius – (pm) ½ the diameter of an atom______________________________________ ______________________________________________________________________________

• Atomic Radius of Ions

o Since ions have more or less electrons than their neutral atom, ions have a slightly different size (radius) then their atoms

o _______________________ are smaller than neutral atoms

o __________________________are larger than neutral atoms Properties of Metals:

• Most elements are metallic • Metals typically have the following characteristics:

o ___________ ionization energies

o ___________ electronegativities

o high degree of luster: _______________________________

o malleable: ______________________________________________________________

o are ____________________ conductors of heat and electricity

o are solid in form

o ____________________ electrons to form _____________________ ions

• Metallic characteristics are exhibited as you travel ______________________________________

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Properties of Non-Metals:

• Non-metals typically have the following characteristics:

o ___________ ionization energies

o ___________ electronegativities

o low degree of luster

o are brittle

o are ____________________ conductors of heat and electricity

o can be solids, liquids, or gasses

o _____________________ electrons to form ____________________ ions Properties of Metalloids (Semi-Metals):

• Contain both metallic and non-metallic properties

• Are the elements that “share a line” with the “Staircase” in the periodic table: ___________________________________________________________________________

• ______________________ is considered to be a metal

• ______________________ is considered to be a non-metal

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Student Practice

1. An alkali metal

2. An alkaline earth metal

3. An inactive gas

4. An active nonmetal

5. A semi-metal

6. An inner transition element

7. Its most common oxidation state is -2

8. A metal with more than one oxidation state

9. Metal with an oxidation number of +3

10. Has oxidation numbers of +1 and -1

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Your Isotope / Ion: Vanadium – 55 ( +2)

Identify each of the following for YOUR SPECIFIC sample 1. Atomic number __________________ 2. Mass Number __________________ 3. Most common isotope __________________ 4. Number of protons __________________ 5. Number of electrons (for the ion) __________________ 6. Number of neutrons __________________ 7. Electron configuration (for the ion) __________________ 8. Draw the Lewis-dot structure

9. Identify a possible excited state of this sample’s electron configuration ___________________ 10. Identify the number of energy levels in which electrons are found in the ground state _______ 11. Identify your element as a: metal, non-metal, or semi-metal ___________________ 12. Identify the ionization energy ___________________ 13. Identify the electronegativity ___________________ 14. Identify the atomic radius ___________________ 15. What block is this element found in (s, p, d, f)? ___________________ 16. Would this ion be colorful? ___________________ 17. Is this element a solid, liquid, or gas? ___________________ 18. Identify the group number, and name of the group, if possible: ________________ ___________________

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Your Isotope / Ion: Strontium – 85 ( -3 )

Identify each of the following for YOUR SPECIFIC sample 1. Atomic number __________________ 2. Mass Number __________________ 3. Most common isotope __________________ 4. Number of protons __________________ 5. Number of electrons (for the ion) __________________ 6. Number of neutrons __________________ 7. Electron configuration (for the ion) __________________ 8. Draw the Lewis-dot structure

9. Identify a possible excited state of this sample’s electron configuration ___________________ 10. Identify the number of energy levels in which electrons are found in the ground state _______ 11. Identify your element as a: metal, non-metal, or semi-metal ___________________ 12. Identify the ionization energy ___________________ 13. Identify the electronegativity ___________________ 14. Identify the atomic radius ___________________ 15. What block is this element found in (s, p, d, f)? ___________________ 16. Would this ion be colorful? ___________________ 17. Is this element a solid, liquid, or gas? ___________________ 18. Identify the group number, and name of the group, if possible: ________________ ___________________

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Quantitative Periodic Trends

Ionization Energy:

o Left Right: Ionization energy ____________________________

_____________________________________________________________ _____________________________________________________________ _____________________________________________________________

o Top Bottom: Ionization energy ____________________________ _____________________________________________________________

_____________________________________________________________

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Electronegativity:

o Left Right: Electronegativity ____________________________

_________________________________________________________________

o Top Bottom: Electronegativity ____________________________ _____________________________________________________________

_____________________________________________________________

_____________________________________________________________ _____________________________________________________________

_____________________________________________________________ _____________________________________________________________

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Atomic Radius:

o Left Right: Atomic Radius ____________________________

_____________________________________________________________ _____________________________________________________________

o Top Bottom: Atomic Radius ____________________________ _____________________________________________________________

_____________________________________________________________

0

50

100

150

200

250

Atom

ic R

adiu

s (p

m)

Atomic Number

Trends in Atomic Radius

~ 36 ~

Your Isotope / Ion: Arsenic –75 (-3)

Identify each of the following for YOUR SPECIFIC sample 1. Atomic number __________________ 2. Mass Number __________________ 3. Most common isotope __________________ 4. Number of protons __________________ 5. Number of electrons (for the ion) __________________ 6. Number of neutrons __________________ 7. Electron configuration (for the ion) __________________ 8. Draw the Lewis-dot structure

9. Identify a possible excited state of this sample’s electron configuration ___________________ 10. Identify the number of energy levels in which electrons are found in the ground state _______ 11. Identify your element as a: metal, non-metal, or semi-metal ___________________ 12. Identify the ionization energy ___________________ 13. Identify the electronegativity ___________________ 14. Identify the atomic radius ___________________ 15. What block is this element found in (s, p, d, f)? ___________________ 16. Would this ion be colorful? ___________________ 17. Is this element a solid, liquid, or gas? ___________________ 18. Identify the group number, and name of the group, if possible: ________________ ___________________

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Your Isotope / Ion: Oxygen – 16

Identify each of the following for YOUR SPECIFIC sample 1. Atomic number __________________ 2. Mass Number __________________ 3. Most common isotope __________________ 4. Number of protons __________________ 5. Number of electrons (for the ion) __________________ 6. Number of neutrons __________________ 7. Electron configuration (for the ion) __________________ 8. Draw the Lewis-dot structure

9. Identify a possible excited state of this sample’s electron configuration ___________________ 10. Identify the number of energy levels in which electrons are found in the ground state _______ 11. Identify your element as a: metal, non-metal, or semi-metal ___________________ 12. Identify the ionization energy ___________________ 13. Identify the electronegativity ___________________ 14. Identify the atomic radius ___________________ 15. What block is this element found in (s, p, d, f)? ___________________ 16. Would this ion be colorful? ___________________ 17. Is this element a solid, liquid, or gas? ___________________ 18. Identify the group number, and name of the group, if possible: ________________ ___________________

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Unit Practice

1. Compared to an atom of C 6

12, an atom of C

614

has:

(1) more protons (2) fewer protons (3) more neutrons (4) fewer neutrons

2. The characteristic bright-line spectrum of an element is produced when electrons:

(1) fall back to lower energy levels (3) are emitted by the nucleus as beta particles (2) are gained by a neutral atom (4) move to higher energy levels

3. How many electrons would be indicated in the Lewis-dot diagram of an atom with an electron configuration of 2-8-6?

(1) 2 (2) 4 (3) 6 (4) 16

4. When an atom goes from the excited state to the ground state, the total energy of the atom:

(1) decreases (2) increases (3) stays the same

5. If atom X is represented by X 6

12 and atom Y is represented by Y

614

, then X and Y are:

(1) isotopes of the same element (3) ions of the same element (2) isotopes of different elements (4) ions of different elements

6. Which of the following represents the electron configuration of an atom in the excited state?

(1) 1-1 (2) 2-3 (3) 2-5 (4) 2-8-1

7. A sample of element X contains 90% 35X atoms, 8% 36X atoms, and 2% 38X atoms. The average isotopic mass is closest to:

(1) 32 (2) 35 (3) 37 (4) 38

8. The atomic number of an atom is always equal to the total number of:

(1) neutrons in the nucleus (3) neutrons plus protons in the atom (2) protons in the nucleus (4) protons plus electrons in the atom

9. The “kernel” includes all the parts of the atom except the: (1) neutrons (2) protons (3) valence electrons (4) orbital electrons

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10. The amount of energy required to remove the most loosely bonded electron from an atom in the gaseous phase is called: (1) kinetic energy (2) potential energy (3) ionization energy (4) electron affinity

11. What is the total number of electrons in an atom with an atomic number of 13 and a mass number of 27?

(1) 13 (2) 14 (3) 27 (5) 40

12. The mass number of an atom is equal to the number of:

(1) neutrons, only (2) protons, only (3) neutrons plus protons (4) electrons plus protons

13. An atom of Rn 88226

contains:

(1) 88 protons and 138 neutrons (3) 88 electrons and 226 neutrons (2) 88 protons and 138 electrons (4) 88 electrons and 226 protons

14. How many electrons are in a neutral atom of Li 37

?

(1) 7 (2) 10 (3) 3 (4) 4

15. The nucleus of a fluorine atom has a charge of:

(1) 1 + (2) 9 + (3) 19 + (4) 0

16. The number of protons in the nucleus of carbon-13 is:

(1) 19 (2) 13 (3) 7 (4) 6

17. Which pair of atoms are isotopes?

(1) C 6

14 and N

714

(3) Ra 88222

and Rn 86222

(2) K 1940

and Ar 1840

(4) K 1940

and K 1942

~ 40 ~

18. Which set of particles is arranged in order of increasing mass?

(1) H2, H, H+ (3) H2, H+, H (2) H+, H, H2 (4) H, H+, H2

19. The existence of fractional atomic masses is best explained by the: (1) mass of electrons (3) inaccuracies in determining atomic masses (2) existence of isotopes (4) varying number of protons in the nucleus of

atoms 20. Which of the following ions has the greatest atomic radius?

(1) K+ (2) F- (3) Na+ (4) Mg+2

21. Isotopes of an element have different:

(1) number of electrons (3) atomic numbers (2) number of protons (4) number of neutrons

22. Which pair of nuclei have the same number of neutrons?

(1) Li 37

and Be 49

(3) Na 1123

and Na 1122

(2) K 1940

and Ar 2040

(4) Na 1123

and Mg 1224

23. All elements in Period 3 are similar in that they all have the same number of:

(1) occupied principle energy levels (3) electron configurations (2) protons in the nucleus (4) valence electrons

24. Which of the following atoms will lose an electron most readily?

(1) potassium (3) rubidium (2) silicon (4) strontium

25. The element in Period 3 with the most metallic character is:

(1) sodium (3) aluminum (2) silicon (4) phosphorus

~ 41 ~

26. The alkaline earth element having the largest atomic radius is found in Period:

(1) 1 (2) 2 (3) 6 (4) 7

27. As one reads from left to right in Period 2, the ionization energy generally:

(1) decreases, and the atomic size decreases (2) decreases, and the atomic size increases (3) increases, and the atomic size increases (4) increases, and the atomic size decreases

28. Which group contains the most active metals? (1) 1 (2) 17 (3) 3 (4) 18

29. A sodium atom becomes a sodium ion by which of the following ways?

(1) gaining a proton (2) losing a proton (3) gaining an electron (4) losing an electron

30. Elements that have properties of both metals and nonmetals are called:

(1) alkali metals (2) metalloids (3) transition elements (4) halogens

31. The alkaline earth metals are in Group:

(1) 1 (2) 2 (3) 3 (4) 5

32. Which element is not a metalloid?

(1) antimony (2) lead (3) tellurium (4) arsenic 33. Which of the following ions have the same electron configuration as a neutral chlorine atom?

(1) S+1 (2) K2- (3) P2- (4) Ca3-

34. More than two-thirds of the elements are classified as:

(1) non-metals (2) metals (3) metalloids (4) noble gases

~ 42 ~

35. Which of the following metals is a transition element?

(1) K (2) Ca (3) Cr (4) Al

36. Which element in Group 14 has the strongest metallic character?

(1) Ge (2) Pb (3) Si (4) Sn

37. A nonmetal that exists in the liquid state at room temperature is:

(1) aluminum (2) mercury (3) hydrogen (4) bromine

38. In general, the elements with the lowest ionization energies would be classified as:

(1) halogens (2) noble gases (3) metals (4) nonmetals

39. Which atom has the greatest affinity for an electron? (1) Li (2) Br (3) Na (4) Cl

40. What is the ionic charge of a neutral atom which lost two electrons?

(1) +2 (2) -2 (3) 0 (4) +3

41. Which element requires the least amount of energy to remove its most loosely bonded electron?

(2) Li (2) Mg (3) Ba (4) Ca

42. Which is the atomic number of an alkali metal?

(1) 10 (2) 11 (3) 12 (4) 13

43. Within a family, as the atomic number of the elements increase, the:

(1) atomic radii decrease (3) ionization energies decrease (2) atomic masses decrease (4) electronegativity increases

44. Which is the electron configuration of an atom in the excited state?

(1) 2-1 (3) 2-5 (2) 2-3 (4) 2-7-1

45. In the ground state, atoms of which element have an incomplete 3rd principal energy level?

(1) Zn (2) Mn (3) Kr (4) Sr

~ 43 ~

46. Which represents the electron configuration, by energy level, of a metalloid in the ground state?

(1) 2-3 (2) 2-5 (3) 2-8-5 (4) 2-8-6

47. Subtracting the atomic number from the mass number of a given atom gives the number of:

(1) electrons (3) protons (2) neutrons (4) energy levels

48. Which atom contains the greatest number of neutrons?

(1) 56Co (2) 57Mn (3) 57Fe (4) 58Ni

49. If atom X is represented by X 84210

and atom Y is represented by Y 84211

, then X and Y are:

(1) isotopes of the same element (3) ions of the same element (2) isotopes of different elements (4) ions of different elements

50. Complete the following chart:

Composition of Some Neutral Atoms Symbol

H

U

Atomic number

19

Mass number

3

238

Number of neutrons

20

Number of electrons

51. A moon sample was analyzed in a lab. The carbon in the sample was found to be 97.78% carbon-12 and 2.22% carbon-13. According to these data, what is the atomic mass of carbon? Show all of your work.

_______________________

~ 44 ~

Short Answers 1) When electrons move from the fourth energy level to the second energy level, they emit visible light.

Explain why the light emitted when an electron makes this move in a sodium atom is a different color than the light emitted by an electron moving from the fourth to the second level of a hydrogen atom. [2]

_____________________________________________________________________________ _____________________________________________________________________________

2) A chemist analyzes two samples. One sample contains 14 g of element X and 6.0 g of element Y. The second sample contains 28 g of element X a nd 6.0 g of element Y. Does it appear that the two samples are the same substance? Explain the reasons for your answer. [3]

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3) Ernest Rutherford performed an experiment in which alpha particles (helium nuclei) were aimed at gold foil. When a few of the particles bounced back instead of passing through with little or no deflection, Rutherford is quoted as saying, "I was as surprised as if I had aimed a 14-inch artillery shell at a piece of paper and it bounced back." Why was he so surprised, and how did he modify the model of the atom to explain his results? [4]

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4) Samples of two different compounds were heated in a flame, and a spectral analysis was performed on each compound. Many of the lines from the two samples matched, but others did not. Use your knowledge of chemistry to explain how this is possible. [2]

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Base your answers to questions 5 through 7 on the data· table, which shows three isotopes oneon.

Some Isotopes of Neon

Isotope Atomic Mass

(atomic mass units) Percent Natural

Abundance Ne-20 19.99 90.9% Ne-21 20.99 0.3% Ne-22 21.99 8.8%

5) In terms of atomic particles, state one difference between these three isotopes of neon.

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6) Based on the atomic masses and the natural abundances shown in the data table, show a correct numerical setup for calculating the average atomic mass of neon.

7) Based on the natural abundances, the average atomic mass of neon is closest to which

whole number?

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Base your answers to questions 8 and 9 on the information below. Naturally occurring elemental carbon is a mixture of isotopes. The percent composition of the two most abundant isotopes is listed below. • 98.93% of the carbon atoms have a mass of 12.00 amu. • 1.07% of the carbon atoms have a mass of 13.00 amu. 8) Show a correct numerical setup for calculating the average atomic mass of carbon. [1]

9) Describe, in terms of subatomic particles found in the nucleus, one difference and one

similarity in the nuclei of the two isotopes. The response must include both isotopes. [2] _____________________________________________________________________________ _____________________________________________________________________________