Groups
period
100
only one valence electron
Group IA
100
only 2 elements
Period 1
200
element that has 17 electrons
Group IIVA
200
quantum number n of valence electron = 2
Period 2
300
Group IIA
300
first series of transition element
period IV
400
Inert gas
Group VIII
400
Have the Acthinide series
Period VI
500
Has 21 electrons
Group IIIB