Răspuns:
Explicație:
5 H, Li, Na,Be, Mg,B, Al, b)O, S, F, Cl
6 a) 1 gr I sub princ, 3 gr I prin, 12 gr II prin
b) 19 gr I prin, 38 gr II prin, 47 gr I sec
c) 29 grI sec, 35 grVII princ, 78 gr VII sec
7 e multtttt
8 H, He
II Li, Be, B, C, N, O, F, Ne
III Na, Mg, Al, Si, P, S, Cl, Ar
b I H, Li, Na, K, Rb, Cs, Fr
II Be, Mg, Ca, Sr, Ba, Ra,
III B, Al, Ga, In, Ti
9. a Br
b Si
c Cl
d He