Which is not unique to each element? a. proton number b. atomic number c. neutron number d. chemical symbol

The correct answer is Option C.

Explanation:

Atomic number is defined as the number of protons or number of electrons present in a neutral atom. It is represented as Z.

Z = Atomic number = Number of electrons = Number of protons

Mass number is defined as the sum of number of protons and number of neutrons present in an atom. It is represented as A.

A = Mass number = Number of protons + Number of neutrons

For Example: Taking potassium and calcium elements

Number of protons in potassium element = 19

Number of neutrons in potassium element = 20

Number of electrons in potassium element = 19

Number of protons in calcium element = 20

Number of neutrons in calcium element = 20

Number of electrons in calcium element = 20

Neutron number can be same for any two elements.

Hence, the correct answer is Option C.

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