Answer:
A)Protons and electrons
Explanation:
An atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.
All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. In other words we can say that negative and positive charges are equal in magnitude and cancel the each other. For example if neutral atom has 6 protons than it must have 6 electrons. The sum of neutrons and protons is the mass number of an atom while the number of protons are number of electrons is the atomic number of an atom.
when an atom lose or gain the electron ions are formed and number of protons and electrons no longer remain the same.
For example:
An atom of sodium when lose one electron it form positive ion. The number of electrons became 10 and number of protons remain 11.
Na → Na⁺ + 1e⁻
