What is being oxidized in each of the following reactions?

Question

(a) Sr(s) + F2(g) SrF2(s)

F2
SrF2
Sr

.(b) H2(g) + I2(g) 2 HI(g)

H2
HI
I2

.(c) 2 Li(s) + Pb2+(aq) 2 Li+(aq) + Pb(s)

Pb2+
Li+
Pb
Li

thanks:) can you give an explanation. I know a is Sr but I don't get why. If it doesnt give you the charges then how are you suppose to know?