27 practice MCQs on periodic trends, s-, p- and d-block elements, halogens, alkali metals and transition elements. Every question has the correct answer and an explanation.
Start free — 20 questionsPeriodic Table and Periodicity is part of the MDCAT Chemistry syllabus. This page collects Periodic Table and Periodicity MCQs in the style of past MDCAT papers — below are 12 of them with answers and explanations, and the full set of 27 questions is in the HighYield MDCAT QBank.
This chapter covers: periodic trends, s-, p- and d-block elements, halogens, alkali metals and transition elements.
Correct answer: D. Lose electrons readily
Elements with low ionization energy lose electrons readily, since less energy is required to remove an electron from their outer shell.
Correct answer: C. Atoms of II-A elements provide two binding electrons
Group II-A (alkaline earth) atoms contribute two valence electrons to metallic bonding, creating stronger metallic bonds and higher melting points than the singly-bonding Group I-A metals.
Correct answer: A. M(OH)₂(s) → MO(s) + H₂O(l)
Alkaline earth metal hydroxides decompose on heating according to M(OH)2(s) to MO(s) + H2O(l), releasing water and forming the metal oxide.
Correct answer: B. Br₂ + 2I⁻ → I₂ + 2Br⁻
Br2 can oxidize iodide ions to iodine (Br2 + 2I- to I2 + 2Br-), since bromine is a stronger oxidizing agent than iodine, making this reaction feasible based on the halogens' relative oxidizing power.
Correct answer: C. Co
Y (yttrium) is a typical transition element because it belongs to the transition metals group in the periodic table. Transition elements are characterized by their partially filled d-orbitals in one or more of their oxidation states.
Correct answer: D. Rn
Radon is a chemical element with the symbol Rn and atomic number 86. It is a noble gas, not an alkaline earth metal. Radon is a radioactive gas that is colorless, odorless, and tasteless. It is formed as a decay product of uranium and thorium in the Earth's crust. Radon is known for being a health hazard due to its radioactivity and potential to accumulate in enclosed spaces.
Correct answer: C. Zn
Zinc is not considered a typical transition element because it lacks partially filled d orbitals in its neutral or common oxidation states. It typically exhibits a +2 oxidation state, with a completely filled d orbital, resembling more like an s-block element in terms of electronic configuration.
Correct answer: C. Cr, Mo, W
Group VIB of transition elements contains: Cr, Mo, W
Correct answer: C. IV A
Group IV-A of the periodic table, also known as Group 14, contains elements that include non-metals, metalloids, and metals.
Correct answer: B. Thick, small electronic cloud
Fluorine has less electron affinity compared to bromine primarily due to its small atomic size and the associated compact 2p subshell, which leads to greater electron-electron repulsion when an extra electron is added. Additionally, the high electronegativity of fluorine reflects its tendency to hold onto its electrons tightly, which can also affect its affinity for extra electrons. In contrast, bromine's larger size reduces the repulsion experienced when an additional electron is added, resulting in a more favorable electron affinity.
Correct answer: D. Small radius and high charge density
Correct, as lithium has the smallest atomic size in the alkali metal group, leading to high charge density, which makes it behave differently from other alkali metals (e.g., stronger covalent character in compounds and diagonal relationship with magnesium).
Correct answer: A. Li: Red
Flame tests are used to identify alkali metals based on the characteristic colors they produce when burned:- Lithium (Li): Red- Sodium (Na): Yellow- Potassium (K): Violet- Caesium (Cs): Blue
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