Solution:
a) H, He, Li, Be, B, C, N, O, F, Ne, Mg, Al Si, P, S, Cl, Ar, K, Ca
b)
Group 1:H, Li, Na, K
Group 2: Be, Mg, Ca
Group 13: B. Al
Group 14: C, Si
Group 15: N. P
Group 16: 0, S
Group 17: F. U
Group 18: He, Ne, Ar
Solution:
a) H, He, Li, Be, B, C, N, O, F, Ne, Mg, Al Si, P, S, Cl, Ar, K, Ca
b)
Group 1:H, Li, Na, K
Group 2: Be, Mg, Ca
Group 13: B. Al
Group 14: C, Si
Group 15: N. P
Group 16: 0, S
Group 17: F. U
Group 18: He, Ne, Ar