Quiz on d-Block and f-Block Elements

Which of the following elements is not considered a transition metal?

• Zinc (Zn)

• Scandium (Sc)

• Copper (Cu)

• Iron (Fe)

Answer explanation

Zinc (Zn) is often classified as a post-transition metal rather than a transition metal. In contrast, Scandium (Sc), Copper (Cu), and Iron (Fe) are all considered transition metals due to their ability to form variable oxidation states.

What is the common oxidation state of most lanthanoids?

• +2

• +3

• +5

• +4

Answer explanation

The common oxidation state of most lanthanoids is +3. This is due to the loss of three electrons from the 6s and 5d orbitals, making +3 the most stable and prevalent oxidation state for these elements.

Which series of transition metals includes elements from Scandium to Zinc?

• 3d series

• 4d series

• 5d series

• 6d series

Answer explanation

The 3d series of transition metals includes elements from Scandium (Sc) to Zinc (Zn), covering atomic numbers 21 to 30. The 4d, 5d, and 6d series include elements in higher energy levels, not Sc to Zn.

What is the electronic configuration of Chromium (Cr)?

• [Ar] 3d10 4s1

• [Ar] 3d5 4s1

• [Ar] 3d4 4s2

• [Ar] 3d6 4s2

Answer explanation

Chromium has an atomic number of 24. Its electronic configuration is [Ar] 3d5 4s1, which is a result of stability gained by half-filling the 3d subshell. This makes [Ar] 3d5 4s1 the correct choice.

Which of the following compounds is known for its use as an oxidizing agent?

• Potassium dichromate (K2Cr2O7)

• Sodium chloride (NaCl)

• Calcium carbonate (CaCO3)

• Iron(III) oxide (Fe2O3)

Answer explanation

Potassium dichromate (K2Cr2O7) is a well-known oxidizing agent used in various chemical reactions, particularly in organic chemistry and analytical chemistry, due to its ability to accept electrons from other substances.

What is the primary reason for the high melting points of transition metals?

• Low atomic mass

• Involvement of d electrons in bonding

• High ionic character

• Strong covalent bonds

Answer explanation

The high melting points of transition metals are primarily due to the involvement of d electrons in bonding, which allows for stronger metallic bonds and greater stability compared to other elements.

Which of the following elements is a member of the actinoid series?

• Ruthenium (Ru)

• Neptunium (Np)

• Yttrium (Y)

• Zirconium (Zr)

Answer explanation

Neptunium (Np) is a member of the actinoid series, which includes elements with atomic numbers 89 to 103. Ruthenium (Ru), Yttrium (Y), and Zirconium (Zr) are not part of this series.

What is the oxidation state of Manganese in MnO4-?

• +6

• +4

• +2

• +7

Answer explanation

In MnO4-, the overall charge is -1. Oxygen has an oxidation state of -2 (4 O = -8). Let x be the oxidation state of Mn. The equation is x + (-8) = -1, solving gives x = +7. Thus, Mn has an oxidation state of +7.

Label this atom's particles.

a

b

c

d

Neutrons

Protons

Electrons

Nucleus

Which transition metal is known for exhibiting a +1 oxidation state most frequently?

• Copper (Cu)

• Iron (Fe)

• Nickel (Ni)

• Zinc (Zn)

Answer explanation

Copper (Cu) is well-known for frequently exhibiting a +1 oxidation state, particularly in compounds like cuprous oxide (Cu2O). In contrast, iron, nickel, and zinc typically show different oxidation states.