Electrons Shell Rules
Electron shells always occupy shells somtimes calles energy levels
the lowest levels are always filled with energy first
only a certain number of electron are allowed in each shell 1st: 2 2nd 8 3rd 8
atoms are much happier when they have full electron shells
In most atoms the outer sheel is not full and this makes the atom want to react.
An elements electron arrangment determines its chemical properties
Working out Electron configurations
You need to know the electron configuration for the first twenty elements in the periodic table.
H = 1 He = 2
Li = 2,1 Be = 2,2 B = 2,3 C = 2,4 N= 2,5 O = 2,6 F = 2,7 Ne = 10
Na = 2,8,1 Mg = 2,8,2 Al = 2,8,3 Si= 2,8,4 P= 2,8,5 S= 2,8,6 CL = 2,8,7 Ar = 2,8,8
K = 2,8,8,1 Ca = 2,8,8,2