Electon Configurations (cont)
•
Lithium:
3 electrons
–
3
rd
electron:
n
= 2;
l
= 0;
m
l
= 0;
m
s
= ½
–
1s
2
2s
1
•
Be:
4 electrons
–
4
th
electron:
n
= 2 ;
l
= 0;
m
l
= 0;
m
s
= –½
–
1s
2
2s
2
–
2s
subshell is now full
