Neet 2025 PYQ

Energy and radius of first Bohr orbit of $H{e}^{+}$ and $L{i}^{2+}$ are:[Given $R_H=2.18\times 10^{-18}\text{J},a_0=52.9\text{pm}$ ]

Which of the following are paramagnetic?A. $[NiC{l}_4{]}^{2-}$ B. $Ni(CO{)}_4$ C. $[Ni(CN{)}_4{]}^{2-}$ D. $[Ni(H_{2}O{)}_6{]}^{2+}$ E. $Ni(PP{h}_3{)}_4$ Choose the correct answer from the options given below:

Given below are two statements:Statement I: Like nitrogen that can form ammonia, arsenic can form arsine.Statement II: Antimony cannot form antimony pentoxide.In the light of the above statements, choose the most appropriate answer from the options given below:

Which among the following electronic configurations belong to main group elements?
A. [Ne]$3s^1$ B. [Ar]$3d^{3}4s^2$ C. [Kr]$4d^{10}5s^{2}5p^5$ D. [Ar]$3d^{10}4s^1$ E. [Rn]$5f^{0}6d^{2}7s^2$

Dalton's Atomic theory could not explain which of the following?