Question

If an atom A has mass number 'x' and atomic number 'y' ( ${}_y{A}^x$ ) and it forms an ion by losing an electron. What can we say about the mass number of the ion?

• A. Mass number will be greater than x
• B. Mass number will be lesser than x
• C. Mass number will be equal to x
• D. Mass number varies randomly

Answer 1

The correct option is C

Mass number will be equal to x

Nucleons constitute for the mass of an atom. Nucleons are protons and neutrons that are present in the nucleus of an atom. The mass of electrons can be neglected because they are very much lighter than protons and neutrons(nearly 2000 times ). Mass number depends upon number of protons.