Test Preparation on Periodic Table & Periodicity-I-Chemistry Test Series For NEET-2020

Modern periodic table is based on the atomic number of the
elements. The experiment which proved the significance of the
atomic number was

The electronic configuration of an element is
1s² , 2s² 2 p⁶ ,3s² 3p³ . What is the atomic number of the
element which is just below the above element in the periodic
table

If an atom has electronic configuration
1s² 2s² 2p⁶3s²3p⁶3d³4s² , it will be placed in

The number of d-electrons in Fe²⁺ (Z=26) is not equal to the
number of electrons in which one of the following

Elements after atomic number 103 have not been discovered till
now. If an element with atomic number 106 were ever
discovered which of the following electronic configuration will
it possess

(a) [Rn]5 f¹⁴ 6d⁴ 7s²        (b) [Rn]5 f¹⁴ 6d⁵7s¹

(c) [Rn]5 f¹⁴ 6d⁶ 7s⁰        (d) [Rn]5 f¹⁴ 6d¹ 7s² 7p³