List of top Chemistry Questions on Atomic Structure asked in JEE Main

Find the value of $ n, \ell, m, $ and $ s $ for the 19th electron of a Cr atom.

If first ionization enthalpy of Mg is $738 \, \text{kJ/mol$ then second ionization enthalpy of Mg in kJ/mol will be :

Assume internuclear axis to be z-axis, the correct molecular orbital representation of $\pi^*$ antibonding molecular orbital formed by overlapping between two $p$ orbitals will be:

Which of the following have same radius according to Bohr's theory : (A) Radius of $1^{st}$ orbit of H-atom.
(B) Radius of $1^{st}$ orbit of He$^{+}$.
(C) Radius of $II^{nd}$ orbit of He$^{2+}$.
(D) Radius of $II^{nd}$ orbit of Li$^{2+}$.
(E) Radius of $II^{nd}$ orbit of Be$^{3+}$.

Two atoms are bonding along the Z-axis. How will the $ \pi^* $ orbital look like (Z is the internuclear axis)?

Anion $ X^- $ contains 45 neutrons and 36 electrons. The atomic mass, period number, and state in which "X" exists is:

How many of the following are paramagnetic:
Lu$^{3+}$, Yb$^{2+}$, Gd$^{2+}$, Ce$^{4+}$, La$^{3+}$, Zn$^{2+}$, Cu$^{2+}$, Mn$^{2+}$, Sc$^{3+}$, and Ti$^{4+}$

Compare the energy of orbitals for multielectronic species. \[ \begin{array}{c|c|c|c} & n & l & m \\ \hline (A) & 3 & 0 & 0 \\ (B) & 3 & 1 & -1 \\ (C) & 4 & 2 & 0 \\ (D) & 3 & 2 & 1 \\ \end{array} \]

Which of the following pair of ions have equal number of unpaired electrons

A metal of work function 2.3 eV is irradiated with radiation of wavelength $ y \times 10^2 $ nm. The maximum kinetic energy of ejected electron is $ 2.8 \times 10^{-20} $ J. Then calculate $ y $ (in nearest integer).

Statement 1: The correct order of 2$^\text{nd}$ ionization energy for boron family elements is: $ \text{B}>\text{Al}>\text{Ga} $.
Statement 2: The correct order of 1$^\text{st}$ ionization energy for carbon family elements is: $ \text{Si}>\text{Ge}<\text{Pb}<\text{Sn} $.
Choose the correct option:

The wavelength of spectral line obtained in the spectrum of Li$^{2+}$ ion, when the transition takes place between two levels whose sum is 4 and difference is 2, is

Among the following, the CORRECT combinations are
A. $ \mathrm{IF_3} \rightarrow $ T-shaped ($ sp^3d $)
B. $ \mathrm{IF_5} \rightarrow $ Square pyramidal ($ sp^3d^2 $)
C. $ \mathrm{IF_7} \rightarrow $ Pentagonal bipyramidal ($ sp^3d^3 $)
D. $ \mathrm{ClO_4^-} \rightarrow $ Square planar ($ sp^2d $)
Choose the correct answer from the options given below:

Spherical node shown in figure-1 is best represented by which point in figure-2.

The energy of first (lowest) Balmer line of H atom is $x$ J. The energy (in J) of second Balmer line of H atom is:

Identify the INCORRECT statements from the following:

A. Notation $ {}^{24}_{12}\mathrm{Mg} $ represents 24 protons and 12 neutrons.
B. Wavelength of a radiation of frequency $ 4.5 \times 10^{15}\ \text{s}^{-1} $ is $ 6.7 \times 10^{-8}\ \text{m} $.
C. One radiation has wavelength $ \lambda_1 $ (900 nm) and energy $ E_1 $. Other radiation has wavelength $ \lambda_2 $ (300 nm) and energy $ E_2 $. $ E_1 : E_2 = 3 : 1 $.
D. Number of photons of light of wavelength 2000 pm that provides 1 J of energy is $ 1.006 \times 10^{16} $.

Choose the correct answer from the options given below:

The energy required by electrons, present in the first Bohr orbit of hydrogen atom, to be excited to second Bohr orbit is ________ J mol$^{-1}$. Given: $R_H = 2.18 \times 10^{-11}$ ergs.

If for Li$^{2+}$ ion, electron is in transition between energy levels such that sum of principal quantum numbers is 4 and difference is 2, then find the wavelength (in cm) emitted for transition between these energy levels.
[Given: $R = 1.1 \times 10^5\ \text{cm}^{-1}$]

The hydrogen spectrum consists of several spectral lines in Lyman series (L$_1$, L$_2$, L$_3$ ...; L$_1$ has lowest energy among Lyman series). Similarly, it consists of several spectral lines in Balmer series (B$_1$, B$_2$, B$_3$ ...; B$_1$ has lowest energy among Balmer lines). The energy of L$_1$ is $x$ times the energy of B$_1$. The value of $x$ is ___ $\times 10^{-1}$. (Nearest integer)

The figures below show: Which of the following points in Figure 2 most accurately represents the nodal surface shown in Figure 1?

X and Y are the number of electrons involved, respectively during the oxidation of I$^-$ to I$_2$ and S$^{2-}$ to S by acidified K$_2$Cr$_2$O$_7$. The value of X + Y is ___.

Consider two Group IV metal ions X$^{2+}$ and Y$^{2+}$. A solution containing 0.01 M X$^{2+}$ and 0.01 M Y$^{2+}$ is saturated with H$_2$S. The pH at which the metal sulphide YS will form as a precipitate is ___. (Nearest integer)
Given:
$K_{sp}(\mathrm{XS}) = 1 \times 10^{-22}$ at 25$^\circ$C
$K_{sp}(\mathrm{YS}) = 4 \times 10^{-16}$ at 25$^\circ$C
$[\mathrm{H_2S}] = 0.1$ M
$K_{a1} \times K_{a2} (\mathrm{H_2S}) = 1.0 \times 10^{-21}$
$\log 2 = 0.30,\ \log 3 = 0.48,\ \log 5 = 0.70$

But-2-yne and hydrogen (one mole each) are separately treated with (i) Pd/C and (ii) Na/liq.NH₃ to give the products X and Y respectively.

Identify the incorrect statements.
A. X and Y are stereoisomers.
B. Dipole moment of X is zero.
C. Boiling point of X is higher than Y.
D. X and Y react with O₃/Zn + H₂O to give different products.
Choose the correct answer from the options given below :

Consider the following spectral lines for atomic hydrogen :
A. First line of Paschen series
B. Second line of Balmer series
C. Third line of Paschen series
D. Fourth line of Bracket series
The correct arrangement of the above lines in ascending order of energy is :

Given below are two statements:
Statement I: When an electric discharge is passed through gaseous hydrogen, the hydrogen molecules dissociate and the energetically excited hydrogen atoms produce electromagnetic radiation of discrete frequencies.
Statement II: The frequency of second line of Balmer series obtained from He⁺ is equal to that of first line of Lyman series obtained from hydrogen atom.
In the light of the above statements, choose the correct answer from the options given below: