Atomic Structure

1) nucleus- the center of the atom and is made up off protons (+) and neutrons (0).

2) electron cloud- surrounds the nucleus and is made up of electrons (-)

every atom has two main parts:

Electron Cloud

the electron cloud is organized into energy levels

1st energy level = 2 electrons

2nd energy level = 8 electrons

valence electrons – the electrons in the outermost energy level.

0

available space for another electron

electron cloud

nucleus

HYDROGEN

atomic number – number of protons in the nucleus.

balanced atom – equal number of protons and electrons; has no charge.

1st energy level

00 00

0 0

CARBON

balanced atom

6 proton = 6 electrons

1st energy level

2nd energy level

LITHIUM

3 +

FLUORINE

9 +

balanced atom

3 proton = 3 electrons

balanced atom

9 proton = 9 electrons

Meaning of Lifebalanced atoms = unhappy atoms

stable atoms = happy atoms

Atoms become stable when they complete their outermost energy level.

2 ways to complete the outmost energy level:

1) find a home for their valence electrons

2) get electrons from other atoms.

LITHIUM

Li

FLUORINE

Fl

1 Lithium & 1 Fluorine = Lithium fluoride

FListructure

formula

LiF

C

H

H

H

H

Carbon & Hydrogen

1 Carbon & 4 Hydrogen = Methane

C H

H

H

H

CH4

structure

formula

Oxidation Numbers

The oxidations number indicates if an atom is going to give up electrons or take in electrons in order to become stable.

Positive oxidation numbers mean the atom is going to give up electrons.

Negative oxidation numbers mean the atom is going to take in electrons

LITHIUM

3 +

FLUORINE

9 +

balanced but not stable

balanced but not stable

Li +1

F -1

Stable and happy

Stable and happy

C H

H

H

H

C -4H +1

CH4

Element Atomic # Valance e-s Oxidation #

N

O

K

Al

C

Ne

7

8

19136

10

5

6

1

3

4

8

-3

-2

+1+3

+/-4

0

ion – an atom or group of atoms that has an electric charge.

Li+ O-2 Mg+2 F-

polyatomic ions- a group of atoms that react as a single ion.

NH4+

ammonium

NO3-

nitrate

SO4-2

sulfate

PO4-3

phosphate

Polyatomic Ions

Ammonium

NH4 +1

Acetate C2H3O2 -1

Hydrogen Carbonate

HCO3 -1

Hydroxide OH -1

Nitrate NO3 -1

Nitrite NO2 -1

Chlorate

ClO3 -1

Carbonate

CO3 -2

Sulfate SO4 -2

Sulfite SO3 -2

Phosphate

PO4 -3

Chemical Formulas

Chemical formulas have positive and negative ions when combined have their oxidation numbers equaling zero.

Ca+

2

O-2+ CaO

calcium oxide

Mg+2+Cl-1 MgCl2 magnesium chloride

K+ +SO4-2 K2SO4

potassium sulfate

NH4++ S-2 (NH4)2S ammonium

sulfideZn+2+PO4

-3 Zn3(PO4)2zinc phosphate

Atoms become stable when they react with other atoms.

When atoms react, they form a chemical bond.

3 Types of Chemical Bonds:1) Ionic

2) Covalent

3) Metallic

Ionic bonds form as a result of the attraction between positive and negative ions.

Na Cl+ -

NaCl

sodium chloride

table salt

Covalent bonds form when electrons are shared between atoms.

O O+ O O

being happy some of the time is better than none of the time.

O2

Metallic bonds form between positively charged metal ions and the free moving valence electrons.

+

++

+

+

++

++

+

++

+

+

-

--

-

-

-

-

-

-

-

-

-

--

-

-

-

-

-

-

-

-

-

-

-

-

-

-

A “sea” of electrons moving around the positively charged metal ions