Question

Can someone please use a periodic table and figure this out? I’m stuck.

Answer 1

I can help with the first one and third for you.

Symbol | atomic # | Mass of # | # of Protons | # of electrons | # of neutrons

Na | 11 | 23 (when rounded) | 11 | 11 | 12

Sr | 38 | 88 (when rounded) | 38 | 38 | 50

(sorry if this didn't help)