The atomic number of three elements A, B and C are 11, 14 and 17 respectively.

(i) State the group to which these elements belong in the modern periodic table.


(ii) Write the formula of the compound formed when the elements B reacts with C.

(i) ● The electronic configuration of element A is: 2,8,1. Number of valence electrons=1 So, it belongs to 1st group.

● electronic configuration of element B is:2,8,4. It contains 4 valence electrons, so it belongs to 14th group.


● electronic configuration of element C is: 2,8,7. It contains 7 valence electrons, so it belongs to 17th group.


(ii) The element B is Si and it has a valency of 4. The element C is Chlorine and it has a valency of 1. So the formula of compound when B reacts with C is SiCl4.


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