Chemical ReactionsIons, Molecules and Compounds

Forming Compounds

Noble gases are unlikely to take part in chemical reactions – WHY?

When atoms collide, electrons interact An atom may give up electrons = cation An atom may gain electrons = anion An atom may share electrons = one pair, two

pair or more

Forming Compounds Ionic Compounds

Composed of cations and anions Attraction is called an ionic bond Metal joined with non-metal Na+ joined with Cl-

Forming Compounds Molecular Compounds

Composed of pairs of electrons being shared Attraction is called a covalent bond Two non-metals O2- joined with O2-

Chemical Names and Formulas

Key Points to Remember: Metal + Non-metal = Ionic Bond Non-metal + Non-metal = Covalent Bond

Ionic Bond = Ionic Compound Covalent Bond = Molecular Compound

Chemical Names and Formulas Names and Formulas for Binary

Molecular Compounds Ends in “~ide”

Prefix System Mono is used only for the

second element Element that is more to the left

is written first If prefix ends in “o” or “a” and

is followed by an “o” , then the vowel on the prefix is dropped

Number Prefix

1 mono

2 di

3 tri

4 tetra

5 penta

6 hexa

Chemical Names and Formulas (p.161)

Ionic Binary Compounds – only have two elements present Ends in “~ide”

Polyatomic Ions – have more then two elements present

Name Chemical Formula

ammonium ion NH4+

hydroxide ion OH-

carbonate CO32-

nitrate NO3-

sulfate SO42-

hydrogen carbonate HCO3-

hydrogen sulfate HSO4-

phosphate PO43-

Multivalent Ions An

element that can form an ion in more than one way.

Element (ous) (ic)

Iron (Fe) +2 +3

Lead (Pb) +2 +4

Tin (Sn) +2 +4

Mercury +1 +2

Copper +1 +2