Question

Alkaline earth metals are
A. Li, Be, K, Mg, Ca
B. Be, Mg, Ca, Sr, Ba
C. Be, K, Mg, Ca, Sr
D. Be, Mg, Ca, K, Rb

Answer 1

Hint: The elements Beryllium, Magnesium, Calcium, Strontium, Barium, and Radium constitute group 2 of the periodic table. These metals are called alkaline earth metals.

Complete Step by Step Answer:
The elements in which the last electron enters the s-orbital are arranged in an s-block.
This block consists of group-1 and group-2.

Group 1 metals include Lithium, Sodium, Potassium, Rubidium, Cesium and Francium.
These are called alkali metals because they readily undergo dissolution in an aqueous solution to form strongly alkaline hydroxides.

Group-2 accommodates Beryllium, Magnesium, Calcium, Strontium, Barium, and Radium.
These elements are called alkaline earth metals as they are alkaline and exist in the earth.
The oxides of calcium, strontium, and barium were recognized much before the metals.

We have to find out which of the following options are alkaline earth metals.
A. Li, Be, K, Mg, Ca
Li is an alkali metal. So, A is incorrect.

B. Be, Mg, Ca, Sr, Ba
These metals are alkali earth metals. So, B is correct.

C. Be, K, Mg, Ca, Sr
K is an alkali metal. So, C is incorrect.

D. Be, Mg, Ca, K, Rb
Rb is an alkali metal. So, D is incorrect.

So, option B is correct.

Note: Alkaline earth metals possess metallic properties. They exhibit good metallic lustre and outstanding electrical and thermal conductivity. Alkali and alkaline earth metals have a single valence electron and two valence electrons per atom respectively. So, metallic bonding in group 2 elements is stronger than that in group 1 elements.