The chloride ion has the same valency as the sodium ion However it has a different electrovalency Why?

Answer 1

The sodium atom has 1 electron in its outermost shell. When forming an ion it donates this electron giving it an overall charge of +1 (having lost a negative charge).

Chlorine atoms have 7 electrons in their outermost shells. When forming an ion these are more likely to take an electron from another atom to form a complete octet (gaining a negative charge) thus it becomes -1.

Both atoms will gain or loose 1 electron, hence why they have the same valency, however the electrovalency depends on whether this charge becomes positive or negative. Hope this helps!

Answer 2

Although both sodium and chloride ions have the same valency (+1), their electrovalency differs because sodium tends to lose one electron to achieve a stable electron configuration, forming a positively charged ion, while chloride tends to gain one electron to achieve stability, forming a negatively charged ion. This difference in electron transfer results in the ions having opposite charges despite having the same valency.