Magnetic properties, interstitial compounds and alloys — NEET & JEE Questions

Question 1 · difficulty L1 · recall

Paramagnetism in transition-metal species is mainly due to

• A. unpaired electrons
• B. paired electrons only
• C. absence of electrons
• D. high atomic mass alone

Question 2 · difficulty L2 · understanding

An interstitial compound is formed when

• A. small atoms occupy holes in a metal lattice
• B. large metal atoms leave the lattice completely
• C. all metal-metal bonds are broken
• D. only noble gases dissolve in metals

Question 3 · difficulty L2 · understanding

Interstitial compounds of transition metals are often

• A. hard and have high melting points
• B. very soft molecular gases
• C. electrically insulating in every case
• D. unstable only at low temperature

Question 4 · difficulty L2 · understanding

Transition metals readily form alloys with one another mainly because many of them have

• A. similar atomic sizes and crystal structures
• B. identical atomic numbers
• C. no valence electrons
• D. only one oxidation state

Question 5 · difficulty L3 · application

Which species is expected to be diamagnetic?

• A. $Zn^{2+}$
• B. $Fe^{3+}$
• C. $Mn^{2+}$
• D. $Cu^{2+}$

Question 6 · difficulty L3 · application

A transition-metal carbide is very hard and retains metallic conductivity. It is best classified as

• A. an interstitial compound
• B. a simple molecular compound
• C. a noble gas solid
• D. an ionic halide

Question 7 · difficulty L3 · application

Which pair is most likely to form substitutional alloys readily because of comparable metallic radii?

• A. Two transition metals of similar size
• B. A transition metal and helium
• C. A metal and a large molecular gas
• D. Two substances with no metallic lattices

Question 8 · difficulty L3 · application

A $d^5$ high-spin metal ion is expected to be

• A. strongly paramagnetic
• B. diamagnetic
• C. nonmagnetic because d orbitals are half-filled
• D. always ferromagnetic

Question 9 · difficulty L4 · application

Which statement correctly distinguishes an interstitial compound from a substitutional alloy?

• A. Interstitial compounds place small atoms in lattice holes, whereas substitutional alloys replace some host metal atoms with similar-sized metal atoms
• B. Both require replacement of every host atom
• C. Interstitial compounds contain no metals
• D. Substitutional alloys require tiny atoms such as H in lattice holes

Question 10 · difficulty L4 · application

A transition-metal sample becomes more strongly attracted to a magnetic field after oxidation. Which microscopic change could account for this?

• A. The oxidation state produced more unpaired d electrons
• B. All d electrons became paired
• C. The metal lost all electrons
• D. The atomic mass decreased