Which of the following is NOT evidence that a chemical change may have occurred? a. Difference in shape
b. Release of energy
c. Bubbles forming
d. Change in color​

Answer : If it loses 2 electrons, the net charge on the atom will be (+2) and If it gains 4 electrons, the net charge on the atom will be (-4).

Explanation :

We are given:

Number of electron in an atom = 9

Number of protons in an atom = 9

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

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.

According to the question,

When the atom loses 2 electrons then the net charge on the atom will be (+2) because it will form a positive ion by losing electrons.

When the atom gains 4 electrons then the net charge on the atom will be (-4) because it will form a negative ion by gains electrons.