There are six electrons, six protons and six neutrons in an atom of an element. What is the atomic mass number of the element?

There are six electrons, six protons and six neutrons in an atom of an element. What is the atomic mass number of the element? Correct Answer 12

The correct answer is option 2 i.e. 12.

Atomic structure

• The number of protons in the nucleus of the atom is equal to the atomic number (Z).
• The number of electrons in a neutral atom is equal to the number of protons.
• The mass number of the atom (M) is equal to the sum of the number of protons and neutrons in the nucleus.
• The number of neutrons is equal to the difference between the mass number of the atom (M) and the atomic number (Z).
• ¹²C: 6 electrons, 6 protons, and 6 neutrons. Hence option 2 is correct.