Lewis Dot Diagrams. Mrs. Kay. Energy in the atom. Charged particles called electrons surround the nucleus in regions called shells or energy levels. Atoms of different elements have different numbers of electrons Each shell is “full” before electrons move to the next shell.
Ex: CaCl2 The 2 is a subscript, it shows that 2 atoms of chlorine bond with one atom of calcium.
The charges need to have a sum of zero
If there is more than one atom of an element in a molecule, we need to add prefixes to these words to tell us how many are present. Here are the prefixes you'll need to remember