Show diagrammatically the electron distributions in a sodium atom and a sodium ion and also give their atomic number.
The atomic number (Z) of an element is equal to the number of protons in its atom. Since the atomic number of sodium atom is 11, it has 11 protons. Since the atom as a whole is electrically neutral, the number of electrons = number of protons = 11. A positively charged sodium ion (Na+) is formed by the removal of one electron from a sodium atom. So, a sodium ion has 11 – 1 = 10 electrons. Thus, the electronic distribution of sodium ion will be 2,8. Since the sodium atom and the sodium ion contain the same number of protons, the atomic number of sodium atom as well as the sodium ion is 11.