Question

How to calculate the number of valence electrons in an ionic compound?

Answer 1

Firstly u should know the atomic no... of atom which has converted into ions .After that see the charge on the ion , if it is a (+) be charge then subtract the no.. of electrons ( the no.. of charge ) from the valence shell electron of that atom . Similarly if the ion is negatively charged the add the no.. of electron on the valence shell
Let us take an example of Na
Atomic no.. of Na is 11
So its EC is 2 ,8 ,1
Valence shell electron is 1
Now it becomes an ion that is Na +
Here Na has 1 positive charge so we will subtract 1 electron from the valence shell of Na as positive charge shows that Na has loss a electron
Now EC of Na is 2 , 8
Valence shell electron is 8
Use the similar concept to anion
_____hope it helps