An element has an electronic configuration of $2, 8, 18, 1$. If its atomic weight is $63$,then how many neutrons will be present in its nucleus?

Which character is different for the two isotopes of an element?

Which of the following is isoelectronic with a carbon atom?

The isobars are atoms with the same number of

Which of the following pairs are isoelectronic species?

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 $_6C^{12}$?