Question

atomic size of sodium atom is greater than of chlorine atom why

Answer 1

Sodium has the atomic orbital arrangement: \[1s^2 2s^2 2p^6 3s^1\]while chlorine has\[1s^2 2s^2 2p^6 3s^2 3p^5\]In effect, you can take 3s and 3p as the 3 shell because the are pulled by close to the same amount. Therefore, the difference in radius due to orbitals is negligible. Chlorine has 17 protons in its nucleus, why sodium has 11. This means that chlorine has more positive charge in its center and pulls harder, making the atom as a whole smaller. Sodium has fewer protons and therefore does this to a lesser extent.

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