Question

Which of the following elements has strongest tendency to form electrovalent bond?

1. Li
2. Na
3. Be
4. Mg

Answer given is Na. Why Na? Why not Mg?

Answer 1

I think the question should properly read....

Explanation:

I think the question should properly read....

`"which of these metals has the greatest tendency to form"`
`"an ionic bond..."`

Now you got 4 metals or metalloids....some of which can engage in covalent bonding. Now sodium metal is the LARGEST of those listed; it is Group 1, third row....and so the least polarizing atom, and the least likely to share electron density in a covalent interaction.

The electronic structure of sodium features a SINGLE valence electron, which is likely to be lost upon cation formation...

`M(g)+DeltararrM^+(g) +e^(-)`

And certainly if you interrogated the quantitative data (which as a physical scientist you are obliged to do), `Delta` WOULD be least for sodium metal, and thus ion formation is energetically favoured.