Name the particles which determine the mass of an atom.

An atom has 3 electrons in M shell. What is the atomic number of the element ?

James Chadwick discovered a sub-atomic particle. State its

(a) location in an atom

(b) charge and

(c) mass.

An atom of an element has 9 protons, 9 electrons and 10 neutrons. State its

(a) atomic number

(b) mass number and

(c) electronic configuration.