The expression $Ze$ gives :

Two atoms have the same atomic mass but different atomic numbers. Such atoms are called as:

The mass number of an anion,$X^{3-}$,is $14$. If there are $10$ electrons in the anion,the number of neutrons in the nucleus of an atom of the element $X$ is:

The atomic number of bromine is $35$ and its atomic weight is $79$. Two isotopes of bromine are present in equal amounts. Which of the following statements represents the correct number of neutrons?

List the isotopes of hydrogen,carbon,and chlorine,and specify the number of protons,electrons,and neutrons for each.

Substances which have identical chemical properties but differ in atomic weights are called