Midterm GenChem

Which of following statements is/are correct for successive values of ionization energies of Al element?

• l₁ > l₂ > l₃ >> l₄

• l₁ > l₂ > l₃ > l₄

• l₁ < l₂ < l₃ << l₄

• l₁ < l₂ < l₃ < l₄

Which of following reactions would present correctly the second ionization of Mg?

• Mg_(S) → Mg_(s)²⁺ + 2e^-

• Mg_(g) → Mg_(g)²⁺ + 2e^-

• Mg_(g)⁺ → Mg_(g)²⁺ + 1e^-

• Mg_(s)⁺ → Mg_(s)²⁺ + 1e^-

Put elements belonging to the IIA group in the increasing order of the first ionization energy I₁

• Sr < Ca < Mg < Be

• Be < Mg < Ca < Sr

• There is no obvious order

Arrange following Hal2 compounds in order of increasing Hal– Hal bond length: F₂, Cl₂, Br₂, I₂

• l₂ < Br₂ < Cl₂ < F₂

• F₂ < Cl₂ < Br₂ < l₂

• l₂ ~ Br₂ ~ Cl₂ ~ F₂

• F₂ ~ Cl₂ ~ Br₂ ~ l₂

MoS₂ is a multiple layers material (see following figure) which is considered as an inorganic graphene. MoS₂ can be used for different application such as: electrode for Li ion battery, catalyst for the H₂ evolution reaction, etc. MoS₂ layers stack together thanks to the π-π(pi pi) stacking, namely via the interaction between p orbitals of S elements of two layers. To extract single layer MoS₂ from the MoS2 multiple-layers stack, one should break the π-π (pi-pi) stacking by inserting an appropriate element between layers of MoS₂. For this purpose, the best option will be:

• Li (atomic radii of 1.3 Angstrom)

• S (atomic radii of 1.02 Angstrom)

• B (atomic radii of 0.90 Angstrom)

• O (atomic radii of 0.73 Angstrom)

Arrange following ions in order of increasing ionic radius : ₄Be²⁺, ₁₂Mg₂₊, ₂₀Ca²⁺, and ₃₈Sr²⁺

• ₄Be²⁺ < ₁₂Mg²⁺ < ₂₀Ca²⁺ < ₃₈Sr²⁺

• ₃₈Sr²⁺ <₂₀Ca²⁺ < ₁₂Mg²⁺<₄Be2⁺

• There is no obvious trend

Arrange following ions in order of increasing ionic radius : O^2-, F^-, Na⁺, Mg²⁺, Al³⁺

• O^2- < F^- < Na⁺ < Mg²⁺ < Al³⁺

• Na⁺ < Mg²⁺ < Al³⁺ < O^2- < F^-

• Al³⁺ < Mg²⁺ < Na⁺ < F^- < O^2-

• Al³⁺ < Mg²⁺ < Na⁺ < O^2- < F^-

Please arrange following atoms in the increasing order of the atomic radii

• ₂He < ₁₀Ne < ₁₈Ar < ₃₆Kr

• ₃₆Kr < ₁₈Ar < ₁₀Ne < ₂He

• ₂He ~ ₁₀Ne ~ ₁₈Ar ~ ₃₆Kr (All these three atoms have the same radii)

Please arrange following atoms in the increasing order of the atomic radii

• ₃Li < ₁₁Na < ₁₉K

• ₁₉K < ₁₁Na < ₃Li

• ₃Li ~ ₁₁Na ~ ₁₉K (All these three atoms have the same radii)

Which of following orders would be correct to present the atoms in the increasing order of effective nuclear charge to the outermost layer electron(s)?

• Li < Be < C < N

• N > C > Be > Li

• N ~ C < Be ~ Li

• N ~ C > Be ~ Li