Question

The elements 4Be, 12Mg and 20Ca, each having two valence electrons in their valence shells, are in periods 2, 3 and 4 respectively of the modern periodic table. Answer the following questions associated with these elements, giving reason in each case:; (a) In which group should they be?; (b) Which one of them is least reactive?; (c) Which one of them has take largest atomic size?(All India - 2015)

Answer 1

Answer:

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Answer 2

a) group 2

b) Ca

c) Ca

a) The elements Be , Mg , Ca should all be in the second group of the period table as they have same valency (valency = 2) .

These elements have to loose two electrons inorder to satisfy their nearest noble gas configuration.

b) Ca is the least reactive.

As we go down a group , the reactivity of will decrease. Ca is the at the bottom of the group amongst these elements and thus has the least reactivity.

c) Ca has the largest atomic size.

The atomic size of elements will increase as we go down a group .