Chapter 6, Problem 57A

Interpretation Introduction

Interpretation:

The missing period, group element and electronic configuration in the given table need to be identified.

Period	Group	Element	Electronic Configuration
3		Mg	[Ne] 3s2
4	14	Ge
	12	Cd	[Kr] 5s2 4d10
2	1		[He] 2s1

Concept introduction:

A periodic table consists of groups and periods. The horizontal rows are termed as periods and the vertical rows are termed as groups. The elements with similar properties are placed together in a group. The elements are also located according to their respective blocks like s, p, d or f block.

Answer to Problem 57A

Period	Group	Element	Electronic Configuration
3	2	Mg	[Ne] 3s2
4	14	Ge	[Ar] 3d10 4s2 4p2
5	12	Cd	[Kr] 5s2 4d10
2	1	Li	[He] 2s1

Explanation of Solution

The electronic configuration of Magnesium is [Ne] 3s² and contains two valence electrons so one can predict that Mg belongs to group 2.

Germanium is located in group 14 and period 4 having atomic number 32. So, its electronic configuration is [Ar] 3d¹⁰ 4s² 4p².

Cadmium has electronic configuration [Kr] 5s² 4d¹⁰. Therefore, it is located in period 5.

From the electronic configuration [He] 2s¹ one can say that the element is Lithium.

Conclusion

Thus, the complete table is as follows:

Period	Group	Element	Electronic Configuration
3	2	Mg	[Ne] 3s2
4	14	Ge	[Ar] 3d10 4s2 4p2
5	12	Cd	[Kr] 5s2 4d10
2	1	Li	[He] 2s1