Classification of Elements and Periodicity in Properties
Test 13

Correct answer Carries: 4.

Wrong Answer Carries: -1.

Which ion among the following isoelectronic species with 18 electrons has the highest polarizing power?

For isoelectronic species (18 electrons), polarizing power increases with charge and decreases with size. \(\ce{Sc^3+}\) (Z=21, +3) has the highest polarizing power compared to \(\ce{K+}\), \(\ce{Ca^2+}\), or \(\ce{Cl^-}\).

\(\ce{Sc^3+}\)
\(\ce{K+}\)
\(\ce{Ca^2+}\)
\(\ce{Cl^-}\)
1

Which element in the fifth period d-block has the highest melting point?

In period 5 d-block (Y to Cd), melting point peaks with strong metallic bonding due to maximum unpaired electrons. Mo (group 6, \(4d^5 5s^1\)) has the highest melting point.

Mo
Y
Zr
Tc
1

Which group 15 element forms a trichloride with the highest covalent character?

Covalent character (Fajans’ rule) increases with smaller size and higher charge density. \(\ce{NCl3}\) (N, smallest) has the highest covalent character among N, P, As, and Sb trichlorides.

N
P
As
Sb
1

What is the IUPAC name of the element with atomic number 113?

Elements with \(Z > 100\) have systematic IUPAC names until officially named. For 113: 1 (un), 1 (un), 3 (tri) → ununtrium. However, it’s now officially Nihonium (Nh).

Nihonium
Ununtrium
Ununpentium
Flerovium
1

Which oxide of a group 14 element is predominantly covalent and acidic?

In group 14, \(\ce{CO2}\) (from C) is covalent and acidic, reacting with bases to form carbonates, unlike \(\ce{SiO2}\) (covalent but less acidic), \(\ce{GeO2}\), or \(\ce{SnO2}\) (amphoteric).

\(\ce{SiO2}\)
\(\ce{CO2}\)
\(\ce{GeO2}\)
\(\ce{SnO2}\)
2

Which oxide of a fourth period element reacts with both acids and bases?

In period 4, \(\ce{ZnO}\) (from Zn, group 12) is amphoteric, reacting with acids (e.g., HCl) and bases (e.g., NaOH), unlike \(\ce{K2O}\) (basic), \(\ce{GeO2}\) (acidic), or \(\ce{As2O3}\) (acidic).

\(\ce{K2O}\)
\(\ce{GeO2}\)
\(\ce{ZnO}\)
\(\ce{As2O3}\)
3

What is the general outer electronic configuration of group 1 elements?

Group 1 elements (alkali metals) have one valence electron, with outer configuration \(ns^1\).

\(ns^2\)
\(ns^2 np^1\)
\(ns^2 np^2\)
\(ns^1\)
4

What is the maximum number of elements in the third period?

The third period (\(n=3\)) includes \(3s\) and \(3p\) orbitals, accommodating 8 electrons, hence 8 elements (Na to Ar).

2
10
8
18
3

Which element has the highest third ionization enthalpy among the following?

Third ionization enthalpy is highest when removing an electron from a noble gas-like configuration. Mg (after losing two electrons, becomes \(\ce{Mg^2+}\) with \(1s^2 2s^2 2p^6\)) has the highest value.

Na
Al
Mg
Si
3

Which element in the second period forms compounds with maximum covalency of 4?

Second period elements (Li to F) have only \(2s\) and \(2p\) orbitals, limiting covalency to 4. C (group 14) achieves this (e.g., \(\ce{CH4}\)), unlike Li, Be, or N.

Li
Be
C
N
3

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