1. Valence Electrons
Benchmark 5

2. Valence Electrons Electrons is the outermost energy level
Involved in chemical reactions

3. How many valence electrons?
Elements within a family have the same number of valence electrons, differing only in energy level!
30Zinc
1s22s22p63s23p64s23d10
84Po
________________6p4
12Mg
35Br
2He
38Sr

5. Electron Dot structures (lewis)
A diagram showing valence electrons as dots.
The inner electrons (core electrons) and atomic nuclei are represented by the symbol for the element Zn Po Mg Br N Cs
*octet rule = atoms try to get 8 e- in their outermost energy level [except H, He, B, Be]

6. Anions & cations K O Cl Xe Sr N
K+1
O-2
Cl-1 Xe
Sr+2
N-3