What purpose do neutrons serve in the nucleus ? What happens if there are too many or too few neutrons?

These nuclei with different numbers of neurons are called isotopes

neutrons' main function is to attract each other and keep the nucleus of an atom intact. a nucleus will become unstable if there are too many or too few neutrons in it.

Explanation:

too many= it will undergo beta decay (the neutrons will changes into proton)

too few= there will be an imbalance between forces which leads to nuclear imbalance

your answer would be a. 12.5 kg

ca has a crystalline lattice with positive ions (since it is a metal, metals are positively charged) and electrons flow freely in its structure since the ca atoms have a large nuclear radius so the electrons are not tightly held, therefore the electrons can flow freely since they are not being highly attracted by the nucleus. moreover, one of the properties of metals are that they are conductors of electricity, thus proving ca is the element.