Chapter 4.1 / 4.2Structure of an Atom

OBJECTIVES1. Describe Dalton’s Atomic Theory.2. Describe and illustrate the structure of an atom

– define the subatomic particles of an atom

Structure of an Atom• Dalton’s Theory: all matter is made up of

individual particles called ______________, which cannot be divided.– All ______________are composed of atoms– All atoms of the same element have the same mass,

and atoms of different elements have different masses

– ____________________ contain atoms of more than one element• In a particular compound, atoms of different elements

always combine in the same way

Structure of an Atom• Atoms are made of subatomic particles:

_____________, ____________ and ____________– _______________ – neutral subatomic particle found

in the nucleus of an atom

– _____________ – positively charged subatomic particle found in the nucleus of an atom

– _____________ – negatively charges subatomic particle found in the space outside the nucleus

Structure of an Atom

• The ___________ charge of an atom is not evenly spread throughout the atom.

• Positive charge is concentrated in a very small, ______________ area.

• The __________________ of the atom is a dense, positively charged mass located in the center of the atom.

Structure of an Atom• neutrons, protons and electrons can be

distinguished by _____________, ____________, and ______________in the atom.

• _________________: the number of protons in an atom of that element– Atoms of different elements have different

___________________________.• ___________________(atomic mass): sum of

the _____________ and the _______________ in the nucleus of the atom

Structure of an Atom

• ______________________: atoms of the same element that have different numbers of neutrons and different _____________ numbers– Isotopes of an element have the same

_________________number but different _________________ numbers because they have different numbers of neutrons

Chapter 4.3 Modern Atomic Theory

OBJECTIVES1. Describe Bohr’s model of the atom2. Describe the electron cloud model

Modern Atomic Theory (4.3)• ___________________ Model of the Atom– A description of the ___________________of

electrons in an atom– Electrons move with __________________ speed in

______________________ orbits around a nucleus (like planets around a sun)

Bohr Model Continued

– Each electron in an atom has a specific amount of energy – _________________________________: the possible energies that electrons in an atom can have

**An electron in an atom can move from one energy level to another when the atom ________________ or ___________________energy

Bohr’s Model of the Atom

____________________

____________________________ gain or lose energy when they move between fixed energy levels

Bohr Model

Electron Cloud Model– ______________________________: a visual model of the

most likely locations for electrons in an atom

Scientists use the electron cloud model to describe the ___________________ locations of electron around the nucleus

The _____________ contains protons and neutrons

The probability of finding an electron is higher in the _________________ regions of the cloud.

Electron Cloud Model

Electron Cloud Model

• Atomic Orbitals– The electron cloud represents all the

__________________________ in an atom– ___________________________: a region of

space around the nucleus where an electron is likely to be found

• An electron cloud is a good ____________________ of how electrons ________________________ in their orbitals

• Electron Configurations– ______________________________: the arrangement

of electrons in the orbitals of an atom

The most ________________________ electron configuration is the one in which the electrons are in orbitals with the ____________________________ possible energies..

When all the electrons in the atom have the lowest possible energies, the atom is in its _________________________________________.

Chapter 5.1 / 5.2The Periodic Table

OBJECTIVES1. Describe the arrangement of elements in the modern periodic

table.2. Describe the general properties of metals, nonmetals and

metalloids.3. Describe how the properties of elements change across a period

in the periodic table

• Mendeleev’s Periodic Table– Mendeleev arranged the elements into rows in

order of __________________ mass so that elements with ________________ properties were in the same ____________________

______________________: is an arrangement of elements in columns, based on a set of properties that _________________ from row to row.

Modern Periodic Table• Mendeleev developed his periodic table before the discovery

of protons – he did not know that all atoms of an element have the same number of protons

• In the modern periodic table, elements are arranged by increasing atomic number (number of __________________________)

________________________: each row in the table of elements

________________________: each column on the periodic table

• Properties of elements repeat in a ________________________ way when __________________ ___________________ are used to arrange elements into groups

This pattern of repeating properties is the ____________________________

_____________________________is a value that depends on the distribution of an element’s isotopes in nature and the masses of those isotopes

____________________________– is defined as one twelfth mass of a carbon-12 atom

There are four pieces of information for each element

________________

__________________

__________________

_________________

The Periodic Law• Each row in the table of elements is a

________________________• Each column in the periodic table is called a

______________________

Classes of Elements– Elements are classified as ________________________,

___________________________, and ___________________________

_________________________________: are elements that are good _______________________________ of electric current and heat - except for mercury, metals are ___________________________ at room temp - most metals are __________________________ - most metals are __________________________ (they can be drawn into thin wires)

____________________________________ are elements that form a bridge between the elements on the left and right sides of the table

_____________________________ : are elements that are ____________________ conductors of heat and electric current - non-metals have _____________________________ points – many are gases at room temperature - all the ____________________ in the periodic table are non-metals

____________________________: are elements with properties that fall between those of metals and non-metals

Across a period table, from left to right, the elements become ____________________ metallic and ________________ non-metallic in their properties

Chapter 5.3Representative Groups (periodic table)

OBJECTIVES

1. Identify the number of valence electrons in certain groups on the periodic table.

2. Predict the reactivity of some elements based on their location within a group.

REPRESENTATIVE GROUPS

______________________Elements in a group have similar properties because they have the

same number of ____________________________ electrons.

___________________________: an electron that is in the highest occupied energy level of an atom - these electrons play a key role in

chemical reactions

The ___________________________ are numbered 1-8 - this is the number of valence electrons in an electron configuration for

the element in that group

______________________

♦ the elements in Group 1A ♦ these metals have a single ___________

valence electron and are extremely reactive - they are only found as compounds in

________________ (example: NaCl - salt)

♦ the reactivity of alkali metals _________________ from the top of Group 1A to

the bottom

______________________

♦ the elements in Group 2A ♦ all alkali earth metals have

____________valence electrons

♦ the differences in reactivity among the alkaline earth metals are shown by the ways they react with

_______________________

______________________

♦ the elements in Group 3A ♦ these elements have _____________ valence

electrons ♦ _____________________________ is the most

abundant metal in the Earth’s crust

______________________________

♦ the elements in Group 4A ♦ these elements have ______________ valence

electrons ♦ the metallic nature of the elements

___________________________ from top to bottom within the group

♦ except for water, most of the compounds in the body contain _______________________________

_____________________♦ the elements in Group 5A♦ these elements have ________ valence electrons♦ includes elements with a wide range of physical properties♦ ______________________ and ___________________ are the most important elements in Group 5A

_____________________ the elements in Group 6A these elements have six __________ valence electrons____________________ is the most abundant element in the Earth’s crust• complex form of life need oxygen to stay

alive because oxygen is used to release stored energy in food

_________ was one of the first discovered elements discovered because it is found in large natural deposits

______________________♦ the elements in Group 7a♦ these elements have _________valence electrons highly reactive non-metals (fluorine and chlorine are the most reactive) – react easily with ___________________

♦ despite their physical differences, the halogens have ___________________ chemical properties

____________________♦ the elements in Group 8A♦ these elements have _________valence electrons except for helium (He) which has ____________♦ the noble gases are __________________ and ____________________ and extremely unreactive

When electric current is passed through the _________________ gases, they emit different colors

helium – pink krypton - white

neon – orange / red xenon - blue

argon – lavender