Which one of the following is a correct electronic configuration of sodium?

1. 2, 8
2. 8, 2, 1
3. 2, 1, 8
4. 2, 8, 1

Correct Answer: (d) 2, 8, 1  

Explanation:  

Atomic number is defined as the proton number or we can say that the atomic number of an element is equal to the number of protons in the nucleus of its atom. It is denoted by the letter Z.

For e.g., Oxygen has 6 protons, hence, atomic no. (Z) = 6.

The electronic configuration of an element is a symbolic notation of the manner in which the electrons are distributed over different atomic or molecular orbitals. 

For e.g., the electron configuration of the neon atom is 1s² 2s² 2p⁶, this means that the 1s, 2s and 2p subshells are occupied by 2, 2 and 6 electrons respectively.

To find out the electronic configuration of Sodium, we know that, the atomic number of sodium is 11. Hence, its electron configuration will be

Na (Z=11) = 1s²2s²2p⁶3s¹.

Hence, it has 2 electrons in its innermost shell, 8 electrons in its second shell, and 1 electron in the outer-most shell respectively.

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Updated on: 14-Mar-2023

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