The
Periodic Table: Patterns & Trends
Slide 8 of 12
Trends and patterns in
the Periodic table
Down each group
the number of electrons
in the last / outer shell is the SAME.
2, 1
2, 8, 1
2, 8, 8, 1
G
R
O
U
P
1
2,1
2,2 2,3
2,4
2,5
2,6
2,7
2,8
ACROSS each period
from the left to the right the number of electrons in the SAME outer shell increases by 1 each time (until the shell is full).
G
R
O
U
P
3
2, 3
2, 8, 3
2, 8, 8, 3