Structure of atom practice · Mixed difficulty

Option C (Excited state of neon) is correct because neon's ground state configuration is 1s²2s²2p⁶, and the given configuration shows an electron promoted from 2p to 3s.

Option B (n,α,p,e) is correct because the e/m ratio increases in that order, with the neutron having no charge, the alpha particle having a small charge-to-mass ratio, the proton having a larger ratio, and the electron having the highest e/m ratio.

Option C (3 and 9) is correct because for n=3, there are 3 subshells (l=0, 1, 2) and a total of 9 orbitals (1+3+5).

Option D (+/- 3/2) is correct because in a d7 configuration, there are 3 unpaired electrons, leading to a total spin of 3/2.

Option C (Pauli exclusion principle) is correct because the box diagram showing both electrons in the same box with the same spin violates the Pauli exclusion principle.

Option B is correct because for a given value of l, the magnetic quantum number m can take 2l+1 values ranging from -l to +l.

Option D (79 eV) is correct because it accounts for the increased nuclear attraction after the first electron is removed.

Option C ($7.5 \times 10^{21} {sec}^{-1}$) is correct because it is derived from the equation E = h*f, where E is energy, h is Planck's constant, and f is frequency.

Option B (1: 1: 1) is correct because the energy of an electron in a hydrogen-like species depends on Z²/n², and in this case, that ratio is the same for all three.

Option D is correct. The change in energy per mole is calculated by multiplying the energy of a single photon by Avogadro's number, resulting in approximately 3.99 J.

Option D ($\frac{{h}}{{\lambda}}$) is correct because the dynamic mass of a photon is related to its momentum by $p = mc = \frac{{h}}{{\lambda}}$, so $m = \frac{{h}}{{\lambda c}}$. However, the question asks for dynamic mass of a photon, which is $h/\lambda c$. The closest answer is $h/\lambda$, which represents momentum.

Option D ($\frac{{27}}{5}$) is correct because the energy difference is proportional to (1/n1² - 1/n2²).

Option C ($2 \times {10^6}{\mathrm{m}^{ - 1}}$) is correct because wave number is the reciprocal of wavelength, and converting 500 nm to meters and taking the reciprocal gives $2 \times 10^6 m^{-1}$.

Option B (Pd) is correct because Palladium (Pd) has the electronic configuration [Kr] 4d¹⁰, which means it has 10 d-electrons in its outer shell, and since the question asks for 18 electrons in the outer shell, it must be referring to the sum of the s, p, and d electrons in the outermost shell. Pd has 10 d electrons and 8 electrons in the n-1 shell (4s²4p⁶), so it does not have 18 electrons in its outer shell. However, the question is poorly worded. Pd is the best answer because it can achieve a stable configuration with 18 electrons in its valence shell by forming complexes.

Option A (+2) is correct because for a 3d electron, l=2, and the magnetic quantum number (ml) can range from -l to +l, including 0. Therefore, +2 is a valid ml value.

Option D (A positron and an electron) is correct because positronium is a meta-stable bound state of an electron and its antiparticle, a positron.

Option B (Absorption of energy) is correct because an electron moving from a lower energy level (L) to a higher energy level (M) requires energy absorption.

Option B ($l = \frac{{m - 1}}{2}$) is correct because the number of magnetic orbitals (m) is related to the azimuthal quantum number (l) by the formula m = 2l + 1, which can be rearranged to solve for l.

Option A (Both Assertion and Reason are correct; Reason is the correct explanation of Assertion) is correct because the photoelectric effect depends on the frequency of light, not brightness, and the number of ejected electrons depends on brightness.

Option C (465) is correct because summing the atomic numbers from Hydrogen (1) to Zinc (30) yields 465.

Option D (Electrons come out of a metal with different velocities not greater than a certain value which depends only on the frequency of the incident light wave and not on its intensity) is correct because the kinetic energy of emitted electrons depends on the frequency of the incident light, and there's a maximum kinetic energy.

Option A (dull red to red to white and finally blue) is correct because as temperature increases, the emitted radiation shifts towards shorter wavelengths, progressing from red to blue.

Option B (If both A and R are true but R is not the correct explanation of A) is correct because while both statements are true, thermal equilibrium doesn't directly explain why a black body is a perfect radiator.

Option D (All of the above) is correct because all the statements regarding wave functions, radial distribution, and nodes are accurate.

Option B is correct because both Assertion and Reason are true, but the Reason does not explain the Assertion.

Option A (4s) is correct because s orbitals are always spherical in shape, regardless of the principal quantum number.

Option C (4140 Å) is correct because it is calculated using the formula λ = hc/E, where E is the energy difference.

Option D ($2 \times {10^{20}}$) is correct because it represents the number of photons emitted per second calculated using the power of the source and the energy of a single photon.

Option C (An α-particle) is correct because de Broglie wavelength is inversely proportional to mass; thus, the particle with the largest mass (α-particle) will have the smallest wavelength.

Option D (Visible light, ultraviolet rays, X-rays and gamma rays also) is correct because the photoelectric effect can be caused by any electromagnetic radiation with sufficient energy (frequency) to overcome the work function of the metal.