28.1 general physical and chemical properties (Ti - Cu)

State the properties of transition metals

1. Variable oxidation states

2. Form complex ions

3. Behave as catalysts

4. Form coloured compounds

Define d-block element

An atom of an element with a valence electron in the d sub shelll

Define transition metal

Atoms that form one or more ions with an unpaired electron in a d orbital

State and explain the metals in the d-block that are not transition metals

Scandium: Because its common ion, Sc³⁺, has an empty d-subshell.

Zinc: Because its common ion, Zn²⁺, has a full d-subshell

Explain why some transition metals ions can form ions with different oxidation states

Due to relatively low energy difference between d orbitals and s orbitals allowing different oxidation states to be stable

Explain the trend in atomic radius

Across a period, the number of protons increases shielding remains roughly constant

The electrostatic forces of outer electron to valence electrons increases

Explain the mechanism by which iron catalyses the reaction between hydrogen and nitrogen

Nitrogen and hydrogen gas adsorb onto surface of iron.

This weakens the chemical bonds and react to form NH3

Then the NH3 is desorbed

Iodine clock

Homogenous catalyst

Autocatalysis

Examples of transition metals that are not catalysts

Alcl3, h2so4

Sketch the shape of a 3dxy orbital

Sketch the shape of a 3dz2 orbital

Explain why transition elements have variables oxidation states

Explain why transition elements behave as catalysts

Explain why transition elements form complex ions