Chapter U1.18, Problem

Interpretation Introduction

Interpretation:

The common factor in beryllium (Be), magnesium (Mg) and calcium (Ca) needs to be explained.

Concept introduction:

Group 2 elements in the periodic table are known as alkaline earth metals. These metals have 2 electrons in their outermost shell. These elements can loss these electrons to get + 2 charge on them.

Answer

Valence shell electron is 2 for Be, Mg and Ca element.

Explanation of Solution

The given elements Be, Mg and Ca belong to group 2 in the periodic table.

There electronic configurations are as follows:

Electronic configuration of Be is 1s²2s²

Electronic configuration of Mg is 1s²2s²2p⁶3s²

Electronic configuration of Ca is 1s²2s²2p⁶3s²3p⁶4s²

Thus, all these three elements have last electron in s sub-shell which means these are s block elements containing 2 valence electrons.

Conclusion

Thus, Be, Mg and Ca are s block elements containing 2 valence electrons.