List of top Chemistry Questions on Atomic Structure

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)

Electronic configuration of chromium is: