ildarkick

Ответ:

K(39) - p=19, e=19, n=20

K(40) - p=19, e=19, n=21

O(16) - p=8, e=8, n=8

Al(27) p=13, e=13, n=14

S(32) p=16, e=16, n=16

3. а) Bi, As, N

б) Si, Na, K

в) Ga, Al, B