Which compound does not belong to the same homologus series as the other three compounds​

Igonna be honest i dunno that one srry

The disturbance is only parallel to the motion of the wave.

Try adding 700% because of the x in y

Well you can immediately rule out a and d because if a metal were to lose or gain protons, then it would become a different element all together. the answer here is b because the positive symbol with a number refers to how many electrons the metal can give away to become stable.