Question

6. The atomic number of elements A, B, C, D and E are given below

Element A B C D EAtomic no. 7 10 12 41 9From the above table, answer the following questions-(a) Which two elements are chemically similar?(b) Which is an inert gas?(c) Which element belongs to 3rd period of periodic table?(d) Which element among these is a non metal?

Answer 1

Electronic configuration of:
A(7) - 2, 5
B(10) - 2, 8
C(12)-2, 8, 2
D(41)-2, 8, 18, 12, 1
a) The number of valence electrons are not same in any of the given elements.So, none of the elements have similar chemical properties.
b) Element B is an inert gas because it has 8 valence electrons.
c) Element C belongs to third period because its electrons are distributed in three shells
d) Element A has 5 valence electrons, therefore it is a non-metal.