$_6C^{11}$ and $_5B^{11}$ are referred to as:

An element $E$ loses one $\alpha$ and two $\beta$ particles in successive stages. The resulting element will be

Two nuclei which are not identical but have the same number of nucleons represent

In the following radioactive transformation given below $R$ $\xrightarrow{\alpha} X$ $\xrightarrow{\beta} Y$ $\xrightarrow{\beta} Z$; the nuclei $R$ and $Z$ are

Successive emission of an $\alpha$-particle and two $\beta$-particles by an atom of an element results in the formation of its

Which of the following pairs represents isotones?