Aim: How do chemists write and interpret chemical formulas?

How are elements named?

•IUPAC- International Union of Pure and Applied Chemists•Formulas use chemical symbols and numbers to show both qualitative and quantitative information.

Aim: How do chemists write and interpret chemical formulas?

Distinguish between empirical and molecular formulas:

• Empirical- simplest integer ratio; Ionic formulas indicate an array of ions in a compound, not a discrete molecule.

• Molecular- ACTUAL ratio of atoms in a molecule.

Aim: How do chemists write and interpret chemical formulas?

How to name binary ionic compounds?

• Write the name of the cation (positive ion) followed by the name of the anion (negative ion) with suffix “IDE.” This is qualitative information.

• Roman numerals represent the CHARGE ON THE CATION. Subscripts denote the number of atoms or ions. This is quantitative information.

Aim: How do chemists write and interpret chemical formulas?Why does one have to enclose polyatomic ions in

parentheses when writing formulas? Polyatomic Ion- group of atoms covalently

bonded together possessing a charge.

How to name covalent compounds?• Use prefixes to note the number of each type of

atom: mono-, di-, tri-, tetra-, penta-, hexa-, hepta-, octa-, nona-, deca-

Aim: How do chemists write and interpret chemical formulas?

How to draw particle diagrams representing chemical formulas?

• Choose a different color for each element.• Make sure circles representing atoms are

touching within a given compound.Particle Diagram Examples