Free Atomic Structure MCQs with Answers
922 Atomic Structure MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
Atomic structure covers the discovery of the proton, Planck's quantum theory, hydrogen emission spectra and the evidence for quantized energy levels. You will use quantum numbers to describe orbitals, distinguish s, p, d and f orbital shapes, and write electronic configurations, including the correct order of electron filling.
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922 questions · page 22 of 47
- A. Nucleon number
- B. Atomic mass
- C. Proton number
- D. Mass number
Explanation: Elements of the periodic table are arranged in ascending order of their atomic number or proton number (which corresponds to the number of…
Correct answer: Proton number- A. 16X8 and 16Y8
- B. 14X8 and 15Y8
- C. 18X9 and 20Y10
- D. 12X6 and 12Y7
Explanation: In option A, both elements are the exact same, as they have same proton number (8) and same mass number (16) so, they are not isotopes…
Correct answer: 14X8 and 15Y8- A. [Ar] 3d5 4s2
- B. [Ar] 3d5 4s1
- C. [Ar] 3d4 4s2
- D. [Ar] 3d6 4s0
Explanation: Chromium (Cr) has atomic number 24. Theoretically, the electronic configuration of Cr should be 1s2 2s2 2p6 3s2 3p6 3d4 4s2 (NOTE: [Ar]…
Correct answer: [Ar] 3d5 4s1- A. Zee effect
- B. Screening effect
- C. Negative effect
- D. Reducing effect
Explanation: The shielding effect is the reduction in the effective nuclear charge on the electron cloud, due to differences in the attraction forces…
Correct answer: Screening effect- A. 2l+1
- B. 2(l+1)
- C. 2(2l+1)
- D. 2(2l-1)
Explanation: Each subshell of qauntum number 'l' contains '2l+ 1' orbitals. According to Pauli's exclusion principle, no more than two electrons can be…
Correct answer: 2(2l+1)- A. 2 quantum numbers
- B. Only one quantum number
- C. Four quantum numbers
- D. 3 quantum numbers
Explanation: We have four quantum numbers, and all four of them are needed to completely describe an electron.
Correct answer: Four quantum numbers- A. Planks
- B. Bohr
- C. Rutherford
- D. Einstein
Explanation: The expression for the radius of the nth orbit of a hydrogen atom was derived by Bohr.
Correct answer: Bohr- A. Nucleus
- B. Atom
- C. Orbital
- D. Nodal plane
Explanation: The region where the probability of finding an electron is negligible is called a nodal plane.
Correct answer: Nodal plane- A. 4s<3s<2s<1s
- B. 4s>3s>2s>1s
- C. Constant
- D. None of these options is correct
Explanation: As the energy levels increase, the orbitals get bigger. So the increasing order of the size of the hybrid orbital is 4s>3s>2s>1s.
Correct answer: 4s>3s>2s>1s- A. Atomic
- B. Charge
- C. Atomic number or charge
- D. Neither atomic number nor charge
Explanation: The atomic number is the number of protons present in the nucleus of an atom.
Correct answer: Atomic- A. Slower, smaller
- B. Faster, smaller
- C. Faster, bigger
- D. Slower, bigger
Explanation: Correct option is B.The answer is faster and smaller. According to Bohr's theory, the speed of an electron in an atom is inversely…
Correct answer: Faster, smaller- A. Shape
- B. Size
- C. Molecularity
- D. Atomicity
Explanation: Correct option is D. Atomicity is defined as the number of atoms in the molecules of an element.
Correct answer: Atomicity- A. 67,000 times
- B. 68,000 times
- C. 65,000 times
- D. 69,000 times
Explanation: Correct option is B. Hemoglobin is the oxygen carrying molecule in blood.
Correct answer: 68,000 times- A. 5.761 Å
- B. 4.761 Å
- C. 3.761 Å
- D. 6.671 Å
Explanation: Radius of H-atom can be calculated by the following formula: rn = ro × n2 putting ro = 0.53 Å n = 3 r3 = 0.53 Å × 32 = (0.53 × 9) Å ≈ 0.5…
Correct answer: 4.761 Å- A. Applicable to all
- B. O
- C. N
- D. Ne
- E. C
Explanation: According to Hund's rule: Each orbital in a sublevel is separately occupied before any orbital is doubly occupied.
Correct answer: Applicable to all- A. Anode rays
- B. None of these
- C. Cathode rays
- D. X-rays
Explanation: As anode rays or canal rays are found to be consisting of positively charged particles; proton, are also called positive rays.
Correct answer: Anode rays- A. Decrease in distance between nucleus and outermost shell
- B. Increase in nuclear charge
- C. Increase in screening effect
- D. Decrease in number of shells
Explanation: The screening effect is the reduction of nuclear force on the outermost electrons due to inner shells.
Correct answer: Increase in screening effect438. The decrease in radius is large for divalent cations but larger for trivalent cations because of:
- A. Ionization energy
- B. Shielding effect
- C. Successive loss of electrons
- D. Electron affinity
Explanation: Successive loss of electrons refers to the process of an atom losing multiple electrons in a stepwise manner to form cations with…
Correct answer: Successive loss of electrons- A. Slightly increased
- B. Slightly decreased
- C. Increased
- D. Decreased
Explanation: The nuclear charge increases successively as we move along a period due to addition of protons.
Correct answer: Increased- A. 2.8.8.1
- B. 2.3
- C. 2
- D. 2.8.7
Explanation: Period 1 has only two elements, H and He with the electron arrangements 1 and 2.
Correct answer: 2