A transition metal ion exists in its highest oxidation state. It is expected to behave as :

• a chelating agent

• a central metal in a coordination compound

• an oxidising agent

• a reducing agent

In chromite ore, the oxidation number of iron, and chromium are respectively

• +3,+2

• +3,+6

• +2,+6

• +2,+3

An element with atomic number 21 is a

• halogen

• representative element

• transition element

• alkali metal

The spin only magnetic moment of Mn⁴⁺ ion is nearly

• 3BM

• 6BM

• 4BM

• 5BM

The highest magneticmoment is shown by the transition metal ion with the configuration :

• 3d²

• 3d⁵

• 3d⁷

• 3d⁹

In the periodic table metals usually used as catalysts belong to

• f-block

• d-block

• p-block

• s-block

Which of the following forms a colourless solution in aqueous medium?

• Cr³⁺

• C³⁺

• Sc³⁺

• Ti³⁺

In chromite ore, the oxidation number of iron and chromium are respectively

• +3, +2

• +3, +6

• +2, +6

• +2, +3

Mercury is a liquid metal because

• it has a completely filled s orbital

• it has a small atomic size

• it has a completely filled d orbital that prevents d-d overlapping of orbitals

• it has a completely filled d orbital that causes d-d overlapping

Which of the following has the maximum number of unpaired 'd' electrons?

• Zn²⁺

• Fe²⁺

• Ni³⁺

• Cu⁺