Which of the following is isoelectronic with a carbon atom?

If $W$ is the atomic weight and $N$ is the atomic number of an element,then:

An electrically charged atom or a group of atoms is known as

An atom is composed of protons,neutrons,and electrons. If the mass of a neutron is halved and the mass of an electron is doubled,what will be the change in the mass of the nucleus of $_6C^{12}$?

Which of the following sets of ions represents a group of isoelectronic ions?

Two atoms of elements $X$ and $Y$ are isotones of each other. Their mass numbers are $70$ and $72$ respectively. If the atomic number of $X$ is $34$,then the atomic number of $Y$ is ..........