What is the relation between the atomic number and mass number of an element?

An element has an atomic number of 11 and its mass number is 23. What is the arrangement of electrons in the shells? State nuclear composition of an atom of the element.

What is meant by (i) atomic number, and (ii) mass number, of an element? Explain with the help of an example.

If an element M has mass number 24 and atomic number 12, how many neutrons does its atom contain?

Rutherford’s alpha particle scattering experiment led to the discovery of: