Dot Notation

Materials Needed Periodic Table

Identify # of Valence Electrons Valence electrons determine the chemical characteristics of elements. The chemical characteristics in each GROUP are similar. Because- The number of valence electrons in each group are the same.

Ignore Transition & Rare Earth Metals Too complicated with those at the moment.

Consider an example of each group. Consider Electron Configuration: Hydrogen: 1s1: 1 Valence e- Beryllium: 2s2: 2 Valence e- Consider Electron Shells Boron: 5 total e-, 2 for the first shell, 3 in valence shell … Carbon 4, nitrogen 5, oxygen 6, fluorine 7, Helium 2 (Full)

A Convenient Pattern 1 8 2 3 4 5 6 7

Trick to remember: Groups 1 & 2: Their group # = # of valence of e- Groups 13-18: # of valence electrons = group # - 10

Drawing the Dots The number of dots equals the number of valence electrons. Steps: Write the element’s symbol. Start with a dot to the right. Moving clockwise, draw a dot on every side of the symbol until all valence e- are represented.

Al Consider Aluminum Aluminum has 13 electrons: 2 on inner shell 8 on next shell 3 on valence shell Al

Br Consider Bromine Bromine has a Noble Gas Notation: [Ar] 4s2 4p5 Since we know Ar is stable, all the e- represented by its notation are stable. Add the exponents to determine 7 e- on the valence shell. Br

Summarize Write a 3-5 sentence summary how to determine and draw the valence electron of an atom in Dot Notation.