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