Question

Answer is A . Kindly tell the value of 31.

Answer 1

Answer:

A

Explanation:

electrons= protons for element and protons+neutrons= mass number

Answer 2

no. of electron =no. of proton= atomic no. so atomic no. is 15 and no.of proton+no.of neutron=atomic mass, here no. of neutron is 16 and proton no. is 15 so atomic mass =15+16= 31 so option A is correct