Chemistry please helpp

Question

Determine the Mass Number of the Following Elements: 

1. Al - 13 Protons 15 Neutrons

1. B - 5 Protons 6 Neutrons

1. C - 6 Protons 8 Neutrons

1. Sc - 21 Protons 25 Neutrons

Na - 11 Protons 13 Neutrons

Answer 1

Brief summary of the video, add up the number of protons and neutrons you have and that is your mass number!

Mass # = protons + neutrons