Which of the following factors determines the size of an atom?

(a) The volume of the nucleus; (b) the volume of space occupied by the electrons of the atom.

(c) the volume of a single electron, multiplied by the number of electrons in the atom; (d) The

total nuclear charge; (e) The total mass of the electrons surrounding the nucleus.

The number of protons in the nucleus (called the nuclear charge). The number of energy levels holding electrons (and the number of electrons in the outer energy level).

The factor which determines the size of an atom is the volume of the space occupied by the electrons of the atom.

Answer: Option B

Explanation:

From periodic table, we already know that,

In moving down the column, atom's size increases whereas in row, from left to right size of atom gets decreased. In general, the electrons are present in space orbiting itself. There is a lot of empty space present in an atom since the electron which is orbiting is like a tip of a needle (very small).

Down the column, volume increases because valence electron occupied large orbitals. But in row left to right, volume decrease. It is because of more proton's number makes electrons to hold tightly.