Question

b) Recognize the following as having ionic or covalent bonds. Justify your answer

NH3, CH4, MgCl2, Na2O, SO2​

Answer 1

1.NH3-covalent bond.

2.CH4(Methane)-covalent bond.

3.MgCl2(Magnesium chloride)-Ionic bond.

4.Na2O(Sodium oxide)- Ionic bond.

5.SO2(sulphur di oxide)- covalent bond

Explanation:

1.NH3 E.C. 7N=1s^2,2s^2,2p^3the electronic configuration of nitrogen which clearly indicates that Nitrogen has 5 electrons in the outermost orbit.1H=1s^1. the electronic configuration of hydrogen which clearly indicates that hydrogen has only 1 electron in the outermost orbit.

2.Since,nitrogen has 3 more electrons in excess hence it shares 3 of its electron to hydrogen and thus forming the compound NH3 which is an covalent bond.

3.methane E.C.6C=1s^2,2s^2,2p^2.the electronic configuration of carbon which clearly indicates that carbon has 4 electrons in the outermost orbit.1H=1s^1.the electronic configuration of hydrogen which clearly indicates that hydrogen has only 1 electron in the outermost orbit.

4.Since,carbon has 4 electrons in excess it shares the electrons with hydrogen and thus forming CH4 which is an covalent bond.

5.In the formation of magnesium chloride,Magnesium has two electrons in excess and chlorine is need of one electron to attain its nearest Noble gas configuration and magnesium should lose two electrons to attain its Noble gas configuration.

6.Therefore,Magnesium donates its 2 electron to chlorine.since,two electrons have been donated it Cl^2.That is Mg^+ ----------- Cl^2-MgCl2 and thus results in the formation of magnesium chloride which is an ionic bond.

7.This is similar to the formation of magnesium chloride.In the formation of sodium oxide,sodium has 1 electron in excess.since two sodium are involving 2 electrons are in excess and hence the two electrons are donated to oxgen since oxygen is in need of two more electrons to complete its octate or the nearest Noble gas configuration

8.Similarly the two sodium should lose each electron to attain Noble gas configuration and hence it is donated to oxygen and thus forms an ionic bond sodium oxide.

Answer 2

1. In NH3 : It contains covalent bond because bond between Nitrogen and 3 Hydrogen atoms is formed by Sharing of electrons.
2. In CH4 : It contains covalent bond due to sharing of electrons between carbon and  hydrogen.
3. In MgCl2 : It contains ionic bond due to loss and gain of electron by Mg and Cl. Mg contains 2 electrons in outer shell as valence electrons while Chlorine has 7 electrons in valence shells so it needs 1 electron to acquire noble gas configuration, Hence, 2 Chlorine atoms are in use here.
4. In Na2O : It contains Ionic bond due to loss of 1 electron by each atomof Sodium and gain of 2 electrons by Oxygen atom.
5. In SO2 : It contains Covalent Bond due to sharing of electrons between Sulfur and Oxygen atoms.