question_answer

Atomic numbers of elements with hypothetical symbols A, D, C, L, S are 3, 9, 11, 17, 19 respectively. (i) Identify set of elements which have similar chemical properties. (ii) Which set is likely to have metallic character? (iii) Which set is likely to have non-metallic character? (iv) Write the formula of the compound formed by the combination of E and A. (v) Write the formula of the compound formed by the combination of atoms of (a) D                                      (b) L

Answer:

               

Electronic	Configuration	Element Atomic number
A	3	2,1
D	9	2,7
C	11	2,8,1
L	17	2,8,7
S	19	2,8,8,1

Atomic numbers of elements A, D, C, L, S are 3, 9, 11, 17, 19 respectively. (i) A, C, S and D, L are sets which have same chemical properties. (ii) Metals should lose electrons and hence should have 1or 2 or 3 electrons in the outermost shell. Therefore A, C, S are metals. (iii) Non-metals should gain electrons and hence should have 5 or 6 or 7 electrons in the outermost shell. D, L are non-metals. (iv) Valency of C = 1 and L is also 1 (8 - 7 = 1) Therefore the formula is CL. (v) \[{{D}_{2}}\]and\[{{L}_{2}}\].