The atoms with same mass number but different atomic number are called

Assertion (A): Two atoms of different elements having same mass number but different atomic numbers are called isobars. Reason (R): Atomic number is the number of protons present and mass number is the total number of protons and neutrons present in a nucleus.

Which of the following pairs is/are correctly matched ? 1. Isotopes : Atoms with same atomic number but different atomic mass 2. Isobars : Atoms with same number of neutrons but different atomic number 3. Isotones : Atoms with same mass number but different atomic number Select the correct answer using the code given below :

The atoms of different elements having same mass number but different atomic number are known as isobars. The sum of protons and neutrons, in the isobars is always different.

Atom with the same atomic number and different mass numbers are called