Electron (e-)orbit/energylevel

Proton (p+)

Neutron (n0)

nucleus

# of p+

p+ + n0

Diatomic Elements: Elements that are most commonly found in a covalent bond with itself.

I Have No Bright Or Clever Friends

I2 H2 N2 Br2 O2 Cl2 F2

H : neutral atom

H+ : positive ion

H- : negative ion

Atoms can either gain or lose electrons

Gain - negatively charged ion. Loses - positively charged ion

Deuterium Atomic Mass = 2

Atomic Number = 1

Hydrogen Atomic Mass = 1

Atomic Number = 1

Atoms that have the same number of protons but a different number of neutrons are called Isotopes.

Octet rule: atoms react to acquire a full outer shell:

• Give away an e- to another atom.• Take an e- from another atom.• Share an e- with another atom.

Ionic bond

Covalent bond

An ION is an atom that has lost or gained an electron.

Lose e- – positive ion OR cation. (metals)Gain e- – negative ion OR anion. (nonmetals)

Ionic

NaCl

A compound has different characteristic properties than the atoms which form it.

Covalent

HCl

Chemical formula gives the following information:

· The different elements in the compound.· The number of atoms in the compound.

Writing Rule 1: Write the symbol of the metallic element first.

Be Cl

Rule 2:

Place the combining capacity of one element as a subscript of the other element.

Beryllium combines with Chlorine

+ -12

Rule 3: Leave subscripts with a value of 1 out.

Be Cl2 1

Two Naming rules: 1. Write the full name of the metal ion first. 2. Name the non-metal ion dropping the last part of the name and adding the suffix “ide”.

berylliumchloride

Rule 4: Reduce the subscripts if possible.

Mg S

Magnesium combines with Sulfur

Mg S + -22

magnesium sulphide

Transition metals can give away different numbers of electrons.

To avoid confusion:

Brackets are used to show how many electrons the Transition metal is giving away.

Iron (III) chlorideIron (II) chloride

Fe Cl + -12

FeCl2

Fe Cl + -13

FeCl3

Write the name of the ionic compound:

PbO

Pb O+ -1

2

lead oxide(IV)

+4 -2

Covalent Compound:

Contain two or more NON-METAL atoms.

Formed by SHARING valence electrons to fill outer shell – octet rule.

· A molecule is the smallest unit of a covalent compound.

Non-metal + Non-metal = covalent bonding

Prefix Number of Atoms

mono 1di 2tri 3

tetra 4penta 5hexa 6hepta 7octa 8nona 9deca 10

Step 1: first non-metal is named with a prefix to show the number of atoms.

We do not use “mono” for the first non-metal.

nitrogen oxide

N O

Step 2: second non-metal is named with a prefix AND with the “ide” ending.

di

2 4

tetradinitrogen tetroxide

PrefixNumber of

Atoms

mono 1

di 2

tri 3

tetra 4

penta 5

hexa 6

Writing formulas

Step 1: Write the symbol of each element.

Step 2: Use a subscript to show the number of each type of atom given by the prefix.

Do not reduce covalent formulas.

phosphorus oxide

P O di

2 5

penta

PrefixNumber of

Atoms

mono 1

di 2

tri 3

tetra 4

penta 5

hexa 6