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Free Periodic Properties and Trends MCQs with Answers

606 Periodic Properties and Trends MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.

Periodic properties arise from electron configuration and effective nuclear charge, producing trends in atomic and ionic radius, ionization energy, electron affinity, electronegativity, metallic character and reactivity. Comparisons run across periods and down groups, with attention to common exceptions. The topic also relates these trends to the behavior of s-block and p-block elements.

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606 questions · page 17 of 31

321. Ionization energy decreases down the group because:

  • A. Shielding remains constant
  • B. Atomic radius remains constant
  • C. Proton number increases
  • D. Atomic radius increase

Explanation: Ionization energy is the energy needed to remove an electron from its atom.

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Correct answer: Atomic radius increase

322. Magnesium oxide is used in the making of the lining of blast furnaces. It is extracted from seawater as follows. Aqueous calcium hydroxide is added to seawater. Ca(OH)2 (aq) + MgCl2 (aq) + Mg(OH)2(s) + CaCl2 (aq) The magnesium hydroxide is then filtered off and roasted. Which of the following comparisons between calcium and magnesium explains why magnesium hydroxide forms?

  • A. Magnesium is less electropositive than calcium.
  • B. Magnesium is lower than calcium in the reactivity series
  • C. The enthalpy change of hydration for Mg2+ is less exothermic than for Ca2+
  • D. The solubility product for Mg(OH)2 is lower than that for Ca(OH)2
  • E. The magnitude of the lattice energy of Mg(OH)2 is less than that of Ca(OH)2

Explanation: The lesser the solubility product the more likely the precipitation will be.

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Correct answer: The solubility product for Mg(OH)2 is lower than that for Ca(OH)2

323. The graph of first ionization enthalpy versus atomic number as follows:

  • A. Alkali metals are at the maxima and noble gases at the minima.
  • B. Noble gases are at the maxima and alkali metals at the minima.
  • C. Transition elements are at the maxima.
  • D. Minima and maxima do not show any regular behavior.

Explanation: The correct answer is Option B: Noble gases are at the maxima and alkali metals at the minima.

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Correct answer: Noble gases are at the maxima and alkali metals at the minima.

324. Choose correct statement:

  • A. Reducing power in aqueous solution is maximum for Lithium metal.
  • B. electron affinity order O+<O<O-22<O-2
  • C. pH of aqueous solution LiCl>BeCl2>MgCl2>AlCl3

Explanation: The correct answer is Option A. Lithium metal has the maximum reducing power in aqueous solutions due to its position at the top of the…

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Correct answer: Reducing power in aqueous solution is maximum for Lithium metal.

325. The order of which the following oxides are arranged according to decreasing basic nature:

  • A. Na2O, MgO, Al2O3, CuO
  • B. CuO, Al2O3, MgO, Na2O
  • C. Al2O3, CuO, MgO, Na2O
  • D. CuO, MgO, Na2O, Al2O3

Explanation: In the periodic table, as we move from left to right across a period, the basic character of oxides decreases, while the acidic character…

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Correct answer: Na2O, MgO, Al2O3, CuO

326. The atomic masses of Li and K are 7 and 39, respectively. According to law of triads the atomic mass of Na will be:

  • A. 23.
  • B. 32.
  • C. 46.
  • D. 64.

Explanation: According to the law of triads, when elements are grouped into sets of three with similar properties, the atomic mass of the middle…

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Correct answer: 23.

327. Which is correct order of ionization energy:

  • A. Be > Mg > Ca
  • B. Na > K > Rb
  • C. Rb > K > Na
  • D. Both A and B

Explanation: The correct answer is option D: Both A and B. Ionization energy decreases as you move down a group in the periodic table due to increased…

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Correct answer: Both A and B

328. The set representing the correct order of first ionization energy is:

  • A. K > Na > Li
  • B. Be > Mg > Ca
  • C. N > P > As
  • D. Both (b) and (c).

Explanation: Ionization energy generally decreases as you move down a group in the periodic table because the outermost electrons are farther from the…

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Correct answer: Both (b) and (c).

329. Correct order of atomic radius is:

  • A. V < Ti
  • B. Cl > S
  • C. Rb > Cs
  • D. Ne > Be

Explanation: The correct order of atomic radius for Vanadium and Titanium is V > Ti because atomic radius decreases as you move from left to right…

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Correct answer: V < Ti

330. Which of the following sequence regarding the first ionization potential of coinage metal is correct?

  • A. Cu >Ag >Au.
  • B. Cu <Ag <Au.
  • C. Cu >Ag <Au.
  • D. Ag >Cu <Au.

Explanation: Atomic sizes of Ag and Au are closer to each other but nuclear charge is more on Au so ionisation potential of Au is highest.(Au :889…

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Correct answer: Cu <Ag <Au.

331. Four successive members of first row transition elements are listed below with their atomic numbers. Which one of them is expected to have the highest third ionization enthalpy:

  • A. Iron (Z = 26)
  • B. Chromium (Z = 24)
  • C. Manganese (Z = 25)
  • D. Vanadium (Z = 23)

Explanation: The third ionization enthalpy is the energy required to remove the third electron from a neutral atom.

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Correct answer: Manganese (Z = 25)

332. The radii of F, F-,O and O2- are in the order of:

  • A. O2->F-> F>O
  • B. F->O2-> F>O
  • C. O2->O>F->F
  • D. O2-> F- >O>F

Explanation: The order of ionic radii is determined by electron configuration and nuclear charge.

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Correct answer: O2-> F- >O>F

333. In which of the following have higher difference in the value of second and third ionisation potential:

  • A. 1s22s22p63s23p1
  • B. 1s22s22p63s2
  • C. 1s22s22p63s1
  • D. 1s22s22p63s23p2

Explanation: The correct answer is Option B: 1s22s22p63s2. This configuration is representative of a noble gas configuration (Neon, in this case) after…

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Correct answer: 1s22s22p63s2

334. Which of the following statements is incorrect in relation to ionization enthalpy?

  • A. Ionization enthalpy increases for each successive electron removed.
  • B. The greatest increase in ionization enthalpy occurs when removing an electron from a noble gas core.
  • C. A significant jump in ionization enthalpy occurs after removing the last valence electron.
  • D. Removing an electron from an orbital with a lower principal quantum number (n) is easier than from a higher n orbital.

Explanation: Option D is the correct answer because it incorrectly states that removing an electron from a lower n value orbital is easier than from a…

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Correct answer: Removing an electron from an orbital with a lower principal quantum number (n) is easier than from a higher n orbital.

335. Without looking at the periodic table select the elements of III A group of the periodic table. (Atomic no. are given):

  • A. 3, 11, 19, 37.
  • B. 5, 13, 21, 39.
  • C. 7, 15, 31, 49.
  • D. 5, 13, 31, 49.

Explanation: Option D is correct because it includes all the elements with atomic numbers that correspond to Group IIIA: 5 (Boron), 13 (Aluminum), 31…

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Correct answer: 5, 13, 31, 49.

336. Which of the following is correct about the radius of species?

  • A. Al = Ga
  • B. Zr = Hf
  • C. Fe3+ < Fe2+ < Fe+
  • D. All of the above

Explanation: All the options are correct, hence the choice 'All of the above' is the right answer.

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Correct answer: All of the above

337. In Mendeleev's periodic table some pairs of elements do not follow increasing order of atomic weight known as anomolous pair. The correct example of anomolous pair is:

  • A. Cl, Ar
  • B. Th, Pa
  • C. Te, In
  • D. Co, Nb

Explanation: In Mendeleev's periodic table, Th (thorium) and Pa (protactinium) form an anomalous pair because they do not adhere to the order of…

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Correct answer: Th, Pa

338. An element with atomic number 20 is placed in which period of the periodic table?

  • A. 4
  • B. 3
  • C. 2
  • D. 1

Explanation: The element with atomic number 20 is calcium. Its electron configuration is 1s2 2s2 2p6 3s2 3p6 4s2, indicating it occupies the 4th…

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Correct answer: 4

339. Chemical properties of Li and Mg are similar because:

  • A. these belong to same group.
  • B. shows diagonal relationship.
  • C. both has same ionization potential.
  • D. both has same electron affinity.

Explanation: The correct answer is that lithium (Li) and magnesium (Mg) show a diagonal relationship, which is why they exhibit similar chemical…

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Correct answer: shows diagonal relationship.

340. The statement that is not correct for the periodic classification of elements is:

  • A. The properties of elements are the periodic functions of their atomic numbers.
  • B. Non-metallic elements are lesser in number than metallic elements.
  • C. The first ionization energies of elements along a period do not vary in a regular manner with increase in atomic number.
  • D. For transition elements, the d-sub shells are filled with electrons monotonically with increase in atomic number.

Explanation: The correct answer is Option C: The first ionization energies of elements along a period do not vary in a regular manner with increase in…

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Correct answer: The first ionization energies of elements along a period do not vary in a regular manner with increase in atomic number.
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