An atom has 2 protons and 2 neutrons. Its mass number is?

Study for the IGCSE Edexcel Chemistry Test. Access flashcards and multiple choice questions with hints and explanations. Get ready for your exam!

Multiple Choice

An atom has 2 protons and 2 neutrons. Its mass number is?

Explanation:
The mass number is the total number of protons and neutrons in the nucleus, i.e., the total nucleons. Here there are 2 protons and 2 neutrons, so add them: 2 + 2 = 4. Electrons don’t affect the mass number; they influence the atom’s charge instead. So the mass number is 4. The other numbers would reflect only protons (2), no nucleons (0), or twice the total (8), none of which match the actual count of nucleons.

The mass number is the total number of protons and neutrons in the nucleus, i.e., the total nucleons. Here there are 2 protons and 2 neutrons, so add them: 2 + 2 = 4. Electrons don’t affect the mass number; they influence the atom’s charge instead. So the mass number is 4. The other numbers would reflect only protons (2), no nucleons (0), or twice the total (8), none of which match the actual count of nucleons.

Subscribe

Get the latest from Examzify

You can unsubscribe at any time. Read our privacy policy