CBSE Class 11-science Answered

Nuclide:

A nuclide (from nucleus) is an atomic species characterized by the specific constitution of its nucleus, i.e., by its number of protons Z, its number of neutrons N, and its nuclear energy state.

Or nuclide is referred as a "species of nucleus" defined by containing a certain number of neutrons and protons.

Positron:

A positron or antielectron is the antimatter counterpart to an electron. A positron has the same mass as an electron and a spin of 1/2, but it has an electrical charge of +1. When a positron collides with an electron an annihilation occurs which results in the production of two or more gamma ray photons.