Question

(a) Explain the formation of magnesium fluoride using Lewis dot structures.
(b) What is a coordinate covalent bond? Give an example.

Answer 1

Hint: Lewis dot symbols or the structures can be easily drawn if you know about the number of valence electrons present in each atom of the molecule and if you know the valence electrons, then with their help you can quickly draw these structures. Now solve it.

Complete answer:
First of let’s discuss what Lewis dot symbols are:
- Lewis dot structures or symbols are the structural representation of the substances i.e. the molecules or the compounds through their valence electrons.
Now considering the statement as;
- In this, magnesium is the central atom and two fluorine atoms are present around it.
- We know that in magnesium, there are two valence electrons and in fluorine there are seven valence electrons.
- So, magnesium atoms will share its two electrons with each of the two chlorine atoms so that both the hydrogen and the oxygen atoms can complete their octet.
- The Lewis dot structure of the magnesium fluoride is as:
 

Now coming to the next part of the question;
- Coordinate covalent bonds are those bonds in which the one atom gives its both the electrons from the shared pair. In other words, we can also say that the both electrons are derived from the same atom.
- Coordinate covalent bonds are also known as the dipolar bond, dative bond or the coordinate bond.
- Example: In $ NH_{4}^{+}$ , there exists coordinate covalent bond between the hydrogen and nitrogen as indicated by the dotted arrow.

Note: Lewis dot structures help to know about the number of valence shell electrons present in an atom and also tells us how many electrons are present in the form of the bond pair and how many electrons are present in the form of lone pair of electrons.