Periodic Table · JEE Main previous year questions

2021 6 questions

1. Q692021 · 25 Jul 2021 · Shift 1

   The ionic radii of ${\mathrm{K}}^{+}$, $\mathrm{N}{\mathrm{a}}^{+}$, $\mathrm{A}{\mathrm{l}}^{3+}$ and $\mathrm{M}{\mathrm{g}}^{2+}$ are in the order:

   1. A.$\mathrm{N}{\mathrm{a}}^{+}<{\mathrm{K}}^{+}<\mathrm{M}{\mathrm{g}}^{2+}<\mathrm{A}{\mathrm{l}}^{3+}$
   2. B.$\mathrm{A}{\mathrm{l}}^{3+}<\mathrm{M}{\mathrm{g}}^{2+}<{\mathrm{K}}^{+}<\mathrm{N}{\mathrm{a}}^{+}$
   3. C.$\mathrm{A}{\mathrm{l}}^{3+}<\mathrm{M}{\mathrm{g}}^{2+}<\mathrm{N}{\mathrm{a}}^{+}<{\mathrm{K}}^{+}$
   4. D.${\mathrm{K}}^{+}<\mathrm{A}{\mathrm{l}}^{3+}<\mathrm{M}{\mathrm{g}}^{2+}<\mathrm{N}{\mathrm{a}}^{+}$
   Show answer

   Answer: C

2. Q632021 · 25 Jul 2021 · Shift 2

   The ionic radii of ${\mathrm{F}}^{-}$ and ${\mathrm{O}}^{2-}$ respectively are $1.33\mathring{A}$ and $1.4\mathring{A}$, while the covalent radius of N is $0.74\mathring{A}$. The correct statement for the ionic radius of ${\mathrm{N}}^{3-}$ from the following is :

   1. A.It is smaller than ${\mathrm{F}}^{-}$ and N
   2. B.It is bigger than ${\mathrm{O}}^{2-}$ and ${\mathrm{F}}^{-}$
   3. C.It is bigger than ${\mathrm{F}}^{-}$ and N, but smaller than of ${\mathrm{O}}^{2-}$
   4. D.It is smaller than ${\mathrm{O}}^{2-}$ and ${\mathrm{F}}^{-}$, but bigger than of N
   Show answer

   Answer: B

3. Q622021 · 18 Mar 2021 · Shift 1

   The ionic radius of $\mathrm{N}{\mathrm{a}}^{+}$ ions is $1.02\text{ A˚}$. The ionic radii (in $\text{A˚}$) of $\mathrm{M}{\mathrm{g}}^{2+}$ and $\mathrm{A}{\mathrm{l}}^{3+}$, respectively, are

   1. A.$1.05\text{ and }0.99$
   2. B.$0.72\text{ and }0.54$
   3. C.$0.85\text{ and }0.99$
   4. D.$0.68\text{ and }0.72$
   Show answer

   Answer: B

4. Q682021 · 18 Mar 2021 · Shift 2

   The first ionization energy of magnesium is smaller as compared to that of elements X and Y, but higher than that of Z. The elements X, Y and Z, respectively, are :

   1. A.neon, sodium and chlorine
   2. B.argon, chlorine and sodium
   3. C.chlorine, lithium and sodium
   4. D.argon, lithium and sodium
   Show answer

   Answer: B

5. Q672021 · 16 Mar 2021 · Shift 1

   An element of group 15, which is a metal and forms a hydride with strongest reducing power among group 15 hydrides. The element is :

   1. A.As
   2. B.Sb
   3. C.Bi
   4. D.P
   Show answer

   Answer: C

6. Q842021 · 25 Feb 2021 · Shift 2· Numerical answer

   Electromagnetic radiation of wavelength 663 nm is just sufficient to ionise the atom of metal A. The ionization energy of metal A in $\mathrm{kJ}\mathrm{mo}{\mathrm{l}}^{-1}$ is ____. (Rounded off to the nearest integer) $[\mathrm{h}=6.63\times 10^{-34}\mathrm{Js},\mathrm{c}=3.00\times 10^8\mathrm{m}{\mathrm{s}}^{-1},{\mathrm{N}}_{\mathrm{A}}=6.02\times 10^{23}\mathrm{mo}{\mathrm{l}}^{-1}]$

   Show answer

   Answer: 181