Chapter 15, Problem 12STP

Interpretation Introduction

Interpretation:

The charge on Sulphur ion is to be written.

Concept introduction:

There are two types of ions:

Positive ions

Negative ions

The ions which are formed by loss of electrons are positive ions known as cations.

The ions which are formed by gain of electrons are negative ions known as anions.

Answer to Problem 12STP

-2

Explanation of Solution

Sulphur is a non-metal and non- metals have tendency to loss electrons because after accepting the electrons their octet is completed.

Atomic number of yttrium is 16

Its electronic configuration is:

$\left[Ne\right]3s^{2}3p^4$

Its electron dot structure is drawn as:

$\begin{array}{ccc}& •& •\\ & S& •\\ •& •& •\end{array}$

To attain noble gas configuration, there is requirement of two electrons. So sulphur gains two electrons and form $S^{-2}$ ion.

Conclusion

Sulphur is short of two electrons from noble gas configuration therefore it forms $S^{-2}$ ion.