Start learning →

JEE Main Unit 1C1: Periodic Trends in Atomic Properties — practice questions

Explore 25 free Unit 1C1: Periodic Trends in Atomic Properties questions in JEE Main Chemistry. Open each question or exercise to read its content, reference answers and available explanation.

Practise Unit 1C1: Periodic Trends in Atomic Properties with Quill →

Unit 1C1: Periodic Trends in Atomic Properties questions and exercises with answers

Showing questions 1–25 of 25.

The general outer electronic configuration of group 15 elements is:Read the answer and worked solution →Which of the following is **not** a noble gas?Read the answer and worked solution →Among the halogens (F, Cl, Br, I), bond dissociation enthalpy is **lowest** for:Read the answer and worked solution →The **inert pair effect** is most pronounced in:Read the answer and worked solution →Boiling points of hydrogen halides follow which order?Read the answer and worked solution →Which of the following has a **see-saw** molecular geometry around the central atom?Read the answer and worked solution →p-block elements are those whose:Read the answer and worked solution →Group 17 elements are called:Read the answer and worked solution →Most electronegative element in periodic table:Read the answer and worked solution →Boron family (group 13) elements:Read the answer and worked solution →Hybridization in BF₃:Read the answer and worked solution →NH₃ shape:Read the answer and worked solution →SF₆ shape:Read the answer and worked solution →In ozone (O₃), bond order is:Read the answer and worked solution →Hybridization of S in SO₂:Read the answer and worked solution →Inert pair effect causes stability of:Read the answer and worked solution →Oxidation state of Cl in HClO₄ (perchloric acid):Read the answer and worked solution →Reaction of XeF₂ with water:Read the answer and worked solution →Number of P-O-P bridges in P₄O₁₀:Read the answer and worked solution →Ionization enthalpy comparison: O vs F. The 1st IE of O is LESS than that of N (because O has paired 2p electron easier to remove). Similarly:Read the answer and worked solution →PCl₅ in gas phase has shape:Read the answer and worked solution →Which halogen liberates Cl₂ from solution of Cl⁻?Read the answer and worked solution →Spot the element that is NOT a noble gasRead the answer and worked solution →Sort: p-block metal or non-metal?Read the answer and worked solution →Match the formula to its IUPAC nameRead the answer and worked solution →

Worked practice questions

The general outer electronic configuration of group 15 elements is:

  1. $ns^2 np^2$
  2. $ns^2 np^3$
  3. $ns^2 np^4$
  4. $ns^2 np^5$
Show answer and solution

Correct answer: B. $ns^2 np^3$

Group 15 (nitrogen family): N, P, As, Sb, Bi. Outer configuration $ns^2 np^3$, i.e. 5 valence electrons (2 in $s$, 3 in $p$). Group 14: $ns^2 np^2$ (option A — carbon family). Group 16: $ns^2 np^4$ (option C — oxygen family). Group 17: $ns^2 np^5$ (option D — halogens). The half-filled $np^3$ in group 15 gives extra stability (like Cr's half-filled d⁵), making nitrogen unusually unreactive in elemental form.

Open this question →

Which of the following is **not** a noble gas?

  1. Argon
  2. Krypton
  3. Bromine
  4. Xenon
Show answer and solution

Correct answer: C. Bromine

Noble gases (group 18): He, Ne, Ar, Kr, Xe, Rn, Og. All chemically inert in their natural state (Xe and Kr can form a few compounds under extreme conditions). **Bromine** is a halogen (group 17), not a noble gas. It's a reactive non-metal, liquid at room temperature, deep red-brown.

Open this question →

Among the halogens (F, Cl, Br, I), bond dissociation enthalpy is **lowest** for:

  1. $\mathrm{F_2}$
  2. $\mathrm{Cl_2}$
  3. $\mathrm{Br_2}$
  4. $\mathrm{I_2}$
Show answer and solution

Correct answer: A. $\mathrm{F_2}$

Down group 17: bond enthalpy is Cl-Cl (242) > Br-Br (192) > F-F (158) > I-I (151) kJ/mol approximately. The surprise is **F-F**, which is *lower* than Cl-Cl despite the trend. Two fluorine atoms are very small and the lone pairs on each repel strongly when they bond — that lone-pair repulsion weakens the F-F bond unusually. Flowing down (Cl → Br → I), bond enthalpy decreases steadily as atomic size increases (orbital overlap weakens). The fluorine anomaly explains its outsize reactivity.

Open this question →

How to practise

  1. Choose a Unit 1C1: Periodic Trends in Atomic Properties question and try to work out your answer.
  2. Open the question to check the correct answer and read its worked solution.
  3. Continue in the app for bite-sized lessons, explanations and review with Quill. You can start without creating an account.

Put it into practice

Continue with Unit 1C1: Periodic Trends in Atomic Properties practice for JEE Main. Read explanations as you go. No signup form needed to start.

Practise Unit 1C1: Periodic Trends in Atomic Properties →

More Chemistry topics

Aldehydes, Ketones and Carboxylic AcidsElectrochemistryStructure of AtomThe d- and f-Block Elements & Coordination CompoundsSolutionsRedox ReactionsUnit 2B1: Transition Metals & Coordination CompoundsChemical Kinetics