Chemistry Question Bank

Assertion (A): The radius of the first orbit of hydrogen atom is 0.529 Å. Reason (R): Radius of each circular orbit rₙ = 0.529 × (n²/Z) Å, where n = 1,2,3 and Z = atomic number.

Assertion (A): For Balmer series of hydrogen spectrum, the value of n₁ = 2 and n₂ = 3, 4, 5 ... Reason (R): The value of n for a line in Balmer series having the highest wavelength is n₁=4 and n₂=6.

Assertion (A): It is impossible to determine the exact position and exact momentum of an electron simultaneously. Reason (R): The path of an electron in an atom is clearly defined.

PASSAGE: In a mixture of H–He⁺ gas (He⁺ is singly ionised He atom), H atoms and He⁺ ions are excited to their respective first excited states. Subsequently, H atoms transfer their total excitation energy to He⁺ ions (…

[Manipal 2008] The radius of the nucleus of mass number A is given by r = 1.25 × 10⁻¹³ × A^(1/3) cm. The radius of the atom is 1.0 Å. For mass number A = 64, the fraction of atomic volume occupied by the nucleus is

The oil drop experiment was developed by

Early Indian and Greek philosophers were of the view that 'A' are the fundamental building blocks of matter. Here, 'A' refers to

Atoms can be further divided into sub-particles like

The e/m ratio for anode rays (positive rays) in comparison to cathode rays is:

Mass of neutron is about ________ times the mass of the electron.

Positive rays (canal rays) are:

The electrical discharge through gases could be observed only at

The smallest and lightest positive ion obtained from hydrogen is called

In the Rutherford scattering experiment, most α-particles passed straight through the gold foil because

Rutherford's nuclear model of the atom failed to explain

The correct order of increasing wavelength of electromagnetic radiations is

Suppose 10⁻¹⁷ J of light energy is needed by the interior of the human eye to see an object. The number of photons of green light (λ = 550 nm) needed to see the object are

A 4000 Å photon is used to break the I₂ molecule. The bond dissociation energy of I₂ is 246.5 kJ/mol. The % of photon energy converted to kinetic energy of iodine atoms is

A photon of 300 nm is absorbed by a gas and then re-emits two photons. One re-emitted photon has wavelength 496 nm. The wavelength of the second re-emitted photon is

A 20 W light source emits monochromatic light of wavelength 600 nm. The number of photons ejected per second expressed in terms of Avogadro's constant N_Av is approximately

If a certain metal is irradiated with two different light radiations of frequency x and 2x, the maximum kinetic energies of ejected electrons are y and 3y respectively. The threshold frequency of the metal will be

As an electron moves away from the nucleus, its potential energy

When sodium compounds are heated in a Bunsen burner flame, they emit light at 5890 Å. If 1.0 × 10⁻⁴ moles of sodium atoms each emit one photon of this wavelength, how much energy (in kJ) is emitted?

Find the frequency of light that corresponds to photons of energy 5.0 × 10⁻⁵ erg

The emission spectra of He⁺ ions show 6 different photons (from transitions to ground state). The quantum number n of the state finally populated in He⁺ ions from the H–He⁺ mixture experiment (after H transfers excita…