1. n,l,m,s values of differentiating electron of A and B are given below
A:n = 4, l = 0, m = 0, s = +1/2
B : n = 3, l = 2, m = -2, s = +1/2
A and B belongs to
a) A (IA group and 3rd period), B (II A group and 4th period)
b) A (I A group and 4th period), B (III B group and 4th period)
c) A (II A group and 3rd period), B (III B group and 4th period)
d) A(III A group and 4th period), B (II B group and 5th period)

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2. Which of the following statements is wrong?
a) van der waals radius is more than its covalent radius
b) All isoelectronic ions belong to same period of the periodic table
c) IE₁ of N is higher than that of O while IE₂ of O is higher than that of N
d) The electron gain enthalpy of N is zero while that of P is74.3 kJ mol^-1

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