For numbers less than 0.1, such as 0.06, the zeros to the right of the decimal point but before the first non-zero digit

Yes it would be a physical change.

The correct answer is "hydrogen".

The answer is b electromagnetic i believe, i hope i ya out!

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.