Question

the elements Be ,Mg ,Ca ,each having 2 valence electrons in their valence shells, are in periods 2,3,4, respectively of the modern periodic table. answer the following questions associated with these elements, giving reasons in each case.

a) in which grp should they be ?
b) which one of them is least reactive ?
c) which one of them has largest atomic size?

Answer 1

(i) All these elements belongs to group 2. Since they all have 2 valence electrons they belongs to group 2.
(ii) Be is the least reactive element. This is due to its smaller atomic size.
(iii) Among Be, Mg and Ca, the element Ca possess largest atomic size. While moving top to bottom in a group atomic radius increases due to addition of new shell.

Answer 2

a) They should belong to group 2, as they all have 2 valence electrons
b) Be(Beryllium) is the least reactive element because its smaller atomic size.
c) Ca has the largest atomic size.