Classification of elements and Periodicity in properties MCQs for NEET — Chemistry Questions with Answers

(c)    Period number     Group number      Element

             5                            7                      Tc

             6                           13                      Tl

             6                            5                       Ta

$$\begin{gathered} \left[Xe\right]4f^{14}5d^{1}6s^2 \\ Atomic number =71 Period number =6th Group number = 3rd \end{gathered}$$

(b) Rubidium is most electropositive in nature.

(c)  $$\begin{gathered} \left(a\right) Cr : 4s^{1}3d^s (each d‐orbital has le") \\ \left(b\right) {\mathrm{Fe}}^{3+}: 4{\mathrm{s}}^{0}3{\mathrm{d}}^{\mathrm{s} } (\mathrm{each} \mathrm{d}‐\mathrm{orbital} \mathrm{has} \mathrm{le}") \\ \left(\mathrm{c}\right) {\mathrm{Cu}}^{+}:4{\mathrm{s}}^{0}3{\mathrm{d}}^{10} (\mathrm{each} \mathrm{d}‐\mathrm{orbital} \mathrm{has} 2\mathrm{e}") \end{gathered}$$

(c) "Unununium" At number =111

      It is a transition element. Period number = 7th; Group number = 11

(d) Atomic radius and metallic character decreases from left to right across the period and increases from top to bottom down the group.

(c) P is trivalent non - metal Q is divalent metal hence formula of compound is $P_2{Q}_3$.

(b) Zn is bigger

In (a)  use (z/e) concept for isoelectronic specie.

     In (c) size of neutral atom is greater than its cation.

(a) (a) Sc > Ti > V > Cr (size decrease initially in 3d-series)

     (b) Correct order : Zn > Cu > Co $\approx$Ni

     (c) Correct order : $S^{2-} > C{l}^{-} > N^3 >O^{2-}$

(b) If we consider the opposite process:

    $$\begin{gathered} \left(a\right) F_{\left(g\right)}+e^{-}\to {F^{-}}_{\left(g\right)} ; ∆H_1 \\ \left(b\right) P_{\left(g\right)}+e^{-}\to {P^{-}}_{\left(g\right)} ; ∆H_2 \\ \left(c\right) S_{\left(g\right)}+e^{-}\to {S^{-}}_{\left(g\right)} ; ∆H_3 \\ \left(d\right) C{l}_{\left(g\right)}+e^{-}\to C{l^{-}}_{\left(g\right) }; ∆H_4 \\ Order of energy releases is : ∆H_4>∆H_1>∆H_3>∆H_2 \end{gathered}$$

$So, {P^{-}}_{\left(g\right)}\to e^{‐}; Requires least energy.$