What part of the atom determines if it will combine or break apart from other substances?

Explanation:

The atom consist of three parts which are following

The proton and neutron form nucleus of an atom. It is present at center of an atom. They have positive charges, while electrons remained outside the nucleus in particular energy levels or shell around the nucleus.

During combination or breaking of substances ,only arrangements of electrons take place. The valence shell electrons decide whether they have to combine or not, while nucleus remained unchanged during any reactions.

1. a)c-14 has two more protons

2. d)they have different numbers of protons, neutrons, and valence electrons; they are all gases at room temperature.

3. c) iron and nickel.

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.