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 4 of 47
- A. Rutherford
- B. Dalton
- C. Bohr
- D. Schrodinger
Explanation: Dalton proposed that matter is made of tiny indivisible atoms, which was an early atomic theory.
Correct answer: Dalton- A. By burning of gas
- B. By cooling of the gas
- C. By the bombardment of cathode rays on gas molecules
- D. From anode like cathode rays produced from cathode
Explanation: Cathode rays collide with gas molecules and remove electrons from them, producing positively charged ions.
Correct answer: By the bombardment of cathode rays on gas molecules- A. Temperature
- B. Pressure
- C. Volume
- D. Composition of glass
Explanation: Cathode rays produce fluorescence when they strike the glass, and the colour depends mainly on the composition of the glass or fluorescent…
Correct answer: Composition of glass- A. Milk
- B. Honey
- C. Oil
- D. Water
Explanation: Millikan used tiny oil droplets in his oil-drop experiment to measure the electronic charge.
Correct answer: Oil- A. 6.02 x 10^23 C/kg
- B. 1.7588 x 10^20 C/kg
- C. 9.1095 x 10^-31 C/kg
- D. 1.7588 x 10^11 C/kg
Explanation: The charge-to-mass ratio of an electron is e/m = 1.602 x 10^-19 C / 9.1095 x 10^-31 kg = 1.7588 x 10^11 C/kg.
Correct answer: 1.7588 x 10^11 C/kg- A. AgNO3 plate
- B. AgCl plate
- C. ZnO
- D. ZnS
Explanation: Positive rays produce visible flashes when they strike a fluorescent material such as zinc sulfide, ZnS.
Correct answer: ZnS- A. Hitorff
- B. Stoney
- C. William Crookes
- D. J.Perrin
Explanation: J. J. Thomson studied positive rays, while J. Perrin investigated their deflection and showed that they carried positive charge.
Correct answer: J.Perrin- A. 10 torr
- B. 1 torr
- C. 0.1 torr
- D. 0.01 torr
Explanation: Gas discharge tubes used to study cathode and positive rays were maintained at very low pressure, commonly about 0.01 torr, so that the…
Correct answer: 0.01 torr- A. Moving e- accelerate towards the nucleus
- B. Continuous spectrum
- C. behavior of electron remain unexplained
- D. all
Explanation: Rutherford's planetary model could not explain why an accelerating electron did not continuously radiate energy and spiral into the…
Correct answer: all- A. 9.11 x 10^-31 Kg
- B. Cast shadow
- C. Heat up the platinum foil
- D. Cannot ionize
Explanation: Cathode rays can ionize gases, so the statement that they cannot ionize is false.
Correct answer: Cannot ionize71. Which of the following properties prove that cathode rays are material in nature_________________?
- A. they cast shadow
- B. they possess momentum
- C. they are negatively charged
- D. all of the above
Explanation: Cathode rays possess momentum, showing that they consist of moving particles with mass, namely electrons.
Correct answer: they possess momentum- A. neutrons
- B. protons and electrons
- C. protons
- D. protons and neutrons
Explanation: The atomic number of an element is defined by its number of protons, so every atomic nucleus contains at least one proton.
Correct answer: protons- A. H
- B. He+¹
- C. Li+²
- D. Be+³
Explanation: For a hydrogen-like species in the first shell, electron energy is E = -13.6 Z^2/1^2 eV, so it becomes more negative as nuclear charge Z…
Correct answer: Be+³74. Atomic number of Mn is 25 what is the electronic configuration in the ground state________________?
- A. 1s2 2s2 2p6 3s2 3p6 3d7
- B. 1s2 2s2 2p6 3s2 3p6 4s2 4p5
- C. 1s2 2s2 2p6 3s2 3p5 3d10
- D. 1s2 2s2 2p6 3s2 3p6 4s23d5
Explanation: Manganese has atomic number 25, so a neutral atom contains 25 electrons.
Correct answer: 1s2 2s2 2p6 3s2 3p6 4s23d5- A. isotope
- B. isobar
- C. isotone
- D. None of these
Explanation: Atoms of different elements having the same number of neutrons are called isotones.
Correct answer: isotone- A. 1s2,2s2,2p6
- B. 1s2,2s2,2p6,3s2
- C. 1s2,2s2,2p6,3s1
- D. None of these
Explanation: Sodium has atomic number 11, so its 11 electrons fill as 1s2, 2s2, 2p6 and then 3s1.
Correct answer: 1s2,2s2,2p6,3s1- A. Ne, 4p2
- B. Ar, 4s2
- C. Ne, 4s2
- D. Kr,4p2
Explanation: Calcium has atomic number 20, and the preceding noble gas is argon, atomic number 18; its remaining two electrons occupy 4s, giving [Ar]…
Correct answer: Ar, 4s2- A. Carbon=0, Oxygen=0
- B. Carbon= +1, Oxygen= -1
- C. Carbon= -1, Oxygen= +1
- D. Carbon=0, Oxygen= -1
Explanation: The major Lewis structure of CO has a triple bond and one lone pair on each atom; formal charge is calculated as valence electrons minus…
Correct answer: Carbon= -1, Oxygen= +1- A. p-electrons in Ne(Z = 10)
- B. s-electrons in Mg(Z = 12)
- C. d-electrons in Fe(Z = 26)
- D. p-electrons in CI(Z = 17)
Explanation: Fe has the configuration [Ar] 3d6 4s2, so Fe2+ loses the 4s electrons and has six 3d electrons.
Correct answer: p-electrons in CI(Z = 17)- A. Nucleon numbera
- B. Mass number
- C. Atomic number
- D. Both A and B
Explanation: The sum of protons and neutrons is called the mass number, and it is also called the nucleon number because protons and neutrons are…
Correct answer: Both A and B