d & f - Block Elements

In general the electronic configuration of d-block elements is

• (n-1)d^1–10 ns¹

• (n-1)d^1–10 ns²

• (n-1)d ^0–10 ns^1–2

• (n-1)d ^1–10 ns ^0–2

Tags

NGSS.HS-PS1-1

Which one is not regarded as a transition element ?

• Sc ( 3d¹)

• Ag ( 4d¹⁰)

• Cu ( 3d¹⁰)

• Cd ( 4d¹⁰)

Which has the highest melting point in 1st row transition metals ?

• Cr

• Fe

• Co

• Mn

Second and the third d series exhibit similar radii (e.g., Zr 160 pm, Hf 159 pm). It is due to

• d-d electron transition

• inert pair effect

• lanthanoid contraction

• hydrogen bonding

In 3d-series, the element which gives the greatest number of oxidation states is

• Cr

• Mn

• Cu

• Fe

The transition element which does not exhibit variable

oxidation states is

• Zn

• Sc

• Ti

• Cu

The E⁰ _(M2+/M) value for Cu is positive (+0.34V). The reasons are

• high Δ_aH^Θ and low Δ_hydH^Θ

• high Δ_aH^Θ and high Δ_hydH^Θ

• low Δ_aH^Θ and low Δ_hydH^Θ

• high Δ_aH^Θ and low Δ_iH^Θ

Stability of higher oxidation states of transition metlas is found in oxides rather than fluorides. It is due to

• the ability of oxygen to form multiple bonds to metals

• its very electronegative nature

• small size of oxygen atom

• absence of d-obitals

Copper (I) compounds are unstable in aqueous solution and undergo disproportionation: 2Cu⁺ → Cu²⁺ + Cu. It is because of

• much more value of Δ_iH₂^Θ of Cu²⁺

• much more negative Δ_aH^Θ of Cu²⁺ (aq) than Cu⁺

• much less negative Δ_hydH^Θ of Cu²⁺ (aq) than Cu⁺

• much more negative Δ_hydH^Θ of Cu²⁺ (aq) than Cu⁺

What is NOT true about Mn₂O₇ ?

• each Mn is tetrahedrally surrounded by O

• it has a Mn–O–Mn bridge

• It is basic in nature

• the oxidation state of Mn is +7