. If the atomic number of an element is

33 it will be placed in the periodic table in the

(a) first group

(b) third group

(c) fifth group

(d) seventh group


Best Answer

Correct Option is: (C)

Element with atomic no. 33 will have electronic configuration 1s22s22p63s23p63d104s24p3.

From the Aufbau principle we know that electrons are filled in order of increasing energy levels, which is determined by n+l. (In case of equal value of n+l, the orbital with greater value of n will have higher energy)

In the above case, 3d and 4p will have the same value of n+l i.e. 5, the 4p orbital will have higher energy. 

It has outermost electron of configuration  ns2np3, which is the same as the Nitrogen family. Hence, it will belong to the Nitrogen family i.e. group 15. 

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