Atomic Structure JEE Main PYQs, 2020 to 2025

The energy of an electron in the first Bohr orbit of the H-atom is -13.6 eV.

The magnitude of energy value of an electron in the first excited state of Be³⁺ is ________ eV (nearest integer value).

Consider the ground state of chromium atom $(Z=24)$. How many electrons are with Azimuthal quantum number $l=1$ and $l=2$ respectively ?

For hydrogen atom, the orbital/s with lowest energy is/are :

(A) $\mathrm{4 s}$

(B) $3 \mathrm{p}_x$

(C) $3 \mathrm{~d}_{x^2-y^2}$

(D) $3 \mathrm{~d}_{z^2}$

(E) $4 \mathrm{p}_z$

Choose the correct answer from the options given below :

Heat treatment of muscular pain involves radiation of wavelength of about 900 nm . Which spectral line of H atom is suitable for this?

Given : Rydberg constant $\left.\mathrm{R}_{\mathrm{H}}=10^5 \mathrm{~cm}^{-1}, \mathrm{~h}=6.6 \times 10^{-34} \mathrm{~J} \mathrm{~s}, \mathrm{c}=3 \times 10^8 \mathrm{~m} / \mathrm{s}\right)$

Niobium $(\mathrm{Nb})$ and ruthenium $(\mathrm{Ru})$ have " $x$ " and " $y$ " number of electrons in their respective 4 d orbitals. The value of $x+y$ is __________.

The incorrect postulates of the Dalton's atomic theory are :

(A) Atoms of different elements differ in mass.

(B) Matter consists of divisible atoms.

(C) Compounds are formed when atoms of different element combine in a fixed ratio.

(D) All the atoms of given element have different properties including mass.

(E) Chemical reactions involve reorganisation of atoms.

Choose the correct answer from the options given below :