Answer: The correct answer is Option 2.
Explanation:
For the given options:
Option 1: Mass number is defined as the sum of number of neutrons (having neutral charge) and number of protons.
Mass number = Number of protons + Number of neutrons
Option 2: Atomic number is defined as the number of protons (having positive charge) or number of electrons (having negative charge).
Atomic number = Number of protons = Number of electrons
Option 3: Avogadro's number is defined as the number of atoms that are present in 1 mole of an atom. The value of it is [tex]6.022\times 10^{23}[/tex]
Option 4: Atomic mass is defined as the sum of mass of neutrons and mass of protons.
From the above information, the number of positive charges in the nucleus of an atom is equal to its atomic number.
Thus, the correct answer is Option 2.
