Question

Q.2) What is the formula for a mass number of an atom ?

1)Number of protons + numbers of electrons
2)Numbers of neutrons + number of electrons
3)Number of protons + number of neutrons
4)None of these​

Answer 1

Answer:

Together, the number of protons and the number of neutrons determine an element's mass number: mass number = protons + neutrons. If you want to calculate how many neutrons an atom has, you can simply subtract the number of protons, or atomic number, from the mass number.

Explanation:

Hope it helps you

Answer 2

Answer:

3) Number of protons + number of neutrons