Question

do all elements have unique mass number and atomic number? what is the reason? ( I NEED A BIG ANSWER)

Answer 1

some elements have same atomic number they are called They have similar chemical properties because isotopes of an element have the same number of electrons as an atom of that element. The electron arrangement is the same owing to same chemical properties. However they have different numbers of neutrons, which affects the mass number .but some have same masses but different atomic number they are called isobars