List of top Chemistry Questions on Periodic Classification of Elements

Which of the following sets contain atomic numbers of only representative elements? \[ \begin{aligned} \text{I.} \quad & 3,\;33,\;53,\;87 \\ \text{II.} \quad & 2,\;10,\;22,\;36 \\ \text{III.} \quad & 9,\;35,\;51,\;88 \\ \text{IV.} \quad & 17,\;25,\;37,\;48 \end{aligned} \] The correct answer is

The correct statement(s) regarding the periodic properties of elements is(are)

Given below are two statements:
Statement (I): The 4f and 5f-series of elements are placed separately in the Periodic table to preserve the principle of classification.
Statement (II): s-block elements can be found in pure form in nature.
In the light of the above statements, choose the most appropriate answer from the options given below:

Identify the elements \(x\) and \(z\) in the following representation. (Sb = antimony)

In which of the following, oxides of three elements X, Y, and Z are arranged in increasing order of acidic nature? Their electronic configurations are:
X: $[Ne] 3s^2 3p^1$, \quad Y: $[Ne] 3s^2 3p^3$, \quad Z: $[Ne] 3s^2$

In which of the following, the elements Al, B, Mg, and K are correctly arranged in the increasing order of their metallic character?

The correct order of ionic radii for the ions, P\(^{3-}\), S\(^{2-}\), Ca\(^{2+}\), K\(^{+}\), Cl\(^{-}\) is:

A galvanic cell is set up from electrodes A and B Electrode A: \( \text{Cr}_2\text{O}_7^{2-} / \text{Cr}^{3+}, \, E^\circ_{\text{red}} = +1.33 \, \text{V} \) Electrode B: \( \text{Fe}^{3+} / \text{Fe}^{2+}, \, E^\circ_{\text{red}} = +0.77 \, \text{V} \) Which of the following statements is false?

What will be the final product in the following reaction sequence: \[ \text{CH}_3\text{CH}_2\text{CN} \xrightarrow{\text{H}^+ / \text{H}_2\text{O}} A \xrightarrow{\text{NH}_3} B \xrightarrow{\text{NaOBR}} C \]

In a set of reactions, acetic acid yields a product D: \[ \text{CH}_3\text{COOH} \xrightarrow{\text{SOCl}_2} \text{Benzene} \xrightarrow{\text{AlCl}_3} (B) \] \[ \text{HCN} \xrightarrow{\text{(C)}} \text{HOH} \xrightarrow{\text{H}_2\text{O}} (D) \] The structure of \( D \) would be:

Group 15 elements have more electron gain enthalpy than group 16 elements. The correct reason for this is

Which of the following does not represent the correct order of the property indicated?

What is the value of electron gain enthalpy of \( \text{Na} \), if \( \text{IE}_\text{Na} = 5.1 \, \text{eV} \)?

Among the elements Ca, Mg, P and Cl, the order of increasing atomic radii is

Match List-I with List-II for the compositions of substances and select the correct answer using the codes given below the lists.

Assertion (A): \(K\), \(Rb\) and \(Cs\) form superoxides. Reason (R): The stability of superoxides increases from \(K\) to \(Cs\) due to decrease in lattice energy.

Match the following:
List I List II
(A) Felspar (I) \([Ag_3Sb_3]\)
(B) Asbestos (II) \(Al_2O_3\cdot H_2O\)
(C) Pyrargyrite (III) \(MgSO_4\cdot H_2O\)
(D) Diaspore (IV) \(KAlSi_3O_8\)
(V) \(CaMg_3(SiO_3)_4\)

Which one of the following order is correct for the first ionisation energies of the elements?

Diamond is hard because

The oxidation number of oxygen in KO\(_3\), Na\(_2\)O\(_2\) is