Answer : The correct option is, It must lose two electrons.
Explanation :
Atomic number is defined as the number of protons or electrons that are present in a neutral atom.
Atomic number = number of protons = number of electrons
For the neutral atom, the number of protons and electrons are equal. But, they are unequal when the atoms present in the form of ions or the atom has some charge.
An ion is formed when an atom looses or gains electron.
When an atom looses electrons, it will form a positive ion known as cation.
When an atom gains electrons, it will form a negative ion known as anion.
As per question,
An ion of oxygen contains 8 protons and has a charge of (2-). If this ion to become a neutral oxygen atom then it must lose two electrons.
Hence, the correct option is, It must lose two electrons.
