The nuclides with same atomic number "Z" but different mass number "A" are called

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

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

Consider the following stetements in reference to the structure of atom 1. Isopes are the atoms of the same element having same atomic number but different mass - numbers . 2. Isobars are the atoms of different elements having different atomic number of different atomic number but same mass - number . Which of above statement is/are correct ?

Q 4 Two atoms are said to be isobars if. * (a) they have same atomic number but different mass number. (b) they have same number of electrons but different number of neutrons (c) they have same number of neutrons but different number of electrons. (d) sum of the number of protons and neutrons is same but the number of protons is different.