Q33 of 52 Page 43

Three elements A, B and C have 3, 4 and 2 electrons respectively in their outermost shell. Give the group number to which they belong in the Modern Periodic Table. Also, give their valencies.


Element A has 3 valence electrons. Thus it has valency 3. It should be in group 13 that contains elements such as B, Al, Ga, In and Tl.


Element A has 4 valence electrons. Thus it has valency 4. It should be in group 14 that contains elements such as C, Si, Ge, Sn and Pb.


Element A has 2 valence electrons. Thus it has valency 2. It should be in group 2 that contains elements such as Be, Mg, Ca, Sr and Ba.


More from this chapter

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31

“Hydrogen occupies a unique position in Modern Periodic Table”. Justify the statement.

 32

Write the formulae of chlorides of Eka-silicon and Eka-aluminium, the elements predicted by Mendeleev.

 34

If an element X is placed in group 14, what will be the formula and the nature of bonding of its chloride?

 35

Compare the radii of two species X and Y. Give reasons for your answer.

(a) X has 12 protons and 12 electrons


(b) Y has 12 protons and 10 electrons