March 28, 2024, 08:02:27 PM
Forum Rules: Read This Before Posting


Topic: Correct answer  (Read 1225 times)

0 Members and 1 Guest are viewing this topic.

Offline peterpan1372

  • Regular Member
  • ***
  • Posts: 87
  • Mole Snacks: +0/-6
Correct answer
« on: September 10, 2017, 08:40:38 PM »
Hello,

Can someone help me out?

I already know that the mass number must be 13, but do not know why 2 and 3 are right too...

thanks for any *delete me*

Sponsored Links