Structure of Atom

Yellow light emitted from a sodium lamp has a wavelength (λ) of 580 nm. Calculate the frequency (ν) and wavenumber (ν̄) of the yellow light.

Find energy of each of the photons which (i) correspond to light of frequency $3 \times 10$¹⁵ Hz. (ii) have wavelength of 0.50 Å.

What is the number of photons of light with a wavelength of 4000 pm that provide 1J of energy?

Electromagnetic radiation of wavelength 242 nm is just sufficient to ionise the sodium atom. Calculate the ionisation energy of sodium in kJ mol⁻¹.

Electrons are emitted with zero velocity from a metal surface when it is exposed to radiation of wavelength 6800 Å. Calculate threshold frequency (ν₀) and work function (W₀) of the metal.

What is the maximum number of emission lines when the excited electron of a H atom in n = 6 drops to the ground state?

Calculate the wavenumber for the longest wavelength transition in the Balmer series of atomic hydrogen.

The mass of an electron is $9.1 \times 10$⁻³¹ kg. If its K.E. is $3.0 \times 10$⁻²⁵ J, calculate its wavelength.

An electron is in one of the 3d orbitals. Give the possible values of n, l and mₗ for this electron.

(i) An atomic orbital has n = 3. What are the possible values of l and mₗ? (ii) List the quantum numbers (mₗ and l) of electrons for 3d orbital. (iii) Which of the following orbitals are possible? 1p, 2s, 2p and 3f

Using s, p, d notations, describe the orbital with the following quantum numbers. (a) n=1, l=0; (b) n=3, l=1; (c) n=4, l=2; (d) n=4, l=3.

Explain, giving reasons, which of the following sets of quantum numbers are not possible. (a) n = 0, l = 0, mₗ = 0, mₛ = +1/2 (b) n = 1, l = 0, mₗ = 0, mₛ = –1/2 (c) n = 1, l = 1, mₗ = 0, mₛ = +1/2 (d) n = 2, l = 1, mₗ = 0, mₛ = –1/2

Show that the circumference of the Bohr orbit for the hydrogen atom is an integral multiple of the de Broglie wavelength associated with the electron revolving around the orbit.

Calculate the energy required for the process He⁺ (g) → He²⁺ (g) + e⁻ The ionization energy for the H atom in the ground state is $2.18 \times 10$⁻¹⁸ J atom⁻¹

The diameter of zinc atom is 2.6 Å. Calculate (a) radius of zinc atom in pm and (b) number of atoms present in a length of 1.6 cm if the zinc atoms are arranged side by side lengthwise.

A certain particle carries $2.5 \times 10$⁻¹⁶ C of static electric charge. Calculate the number of electrons present in it.

Symbols ³⁵₇₉Br and ⁷⁹Br can be written, whereas symbols ³⁵₇₉Br and ³⁵Br are not acceptable. Answer briefly.

An ion with mass number 37 possesses one unit of negative charge. If the ion conatins 11.1% more neutrons than the electrons, find the symbol of the ion.

Nitrogen laser produces a radiation at a wavelength of 337.1 nm. If the number of photons emitted is $5.6 \times 10$²⁴, calculate the power of this laser.

(i) Calculate the total number of electrons present in one mole of methane. (ii) Find (a) the total number and (b) the total mass of neutrons in 7 mg of 14C. (Assume that mass of a neutron = $1.675 \times 10$⁻²⁷ kg). (iii) Find (a) the total number and (b) the total mass of protons in 34 mg of NH₃ at STP. Will the answer change if the temperature and pressure are changed?