21 Chemistry -- Classification of Elements and Periodic Table

Why the first ionisation energy of sodium is higher than that of magnesium?

Why the first ionisation energy of sodium is higher than that of magnesium?

Ionisation energy of an element depends on several factors including the atomic size, effective nuclear charge, electronic configuration, penetration of electrons and so on.

But in case of Sodium and magnesium, the first ionisation energy of Sodium is higher because as the atomic size of sodium is comparatively smaller than Magnesium so it experiences strong effective nuclear charge hence, more amount of energy is required to release valence electron in its ground state.

More questions on Classification of Elements and Periodic Table

Which is bigger Li+ or Na+?

SimilarlyLi+would be the smallest because it has only 2 electrons and therefore the least electron- electron repulsion. When comparing F- and Na +, we have to be careful, as both of them have 10 electron,SoNa+is smaller due to thelargerattractive force of the protons.
Close Open App