Au

Cu

Hg

Ni

Wemer's theory

Valence bond theory

Crystal field theory

Molecular orbital theory

+1, +2 and + 4

+1, +1 and + 1

+2, +1 and $$ + {1 \over 2}$$

+1, +4, and +2

Matter consists of indivisible atoms all the atoms of a given element have.

Chemical reactions involve reorganization of atoms. These are neither created not destroyed in a chemical reaction.

When gases combine or reproduced in a chemical reactionn they do so in a simple ratio by volume provided all gases are the same T & P.

Identical properties including identical mass. Atoms of differemt element differ in mass.