Transition elements
Introduced| English | Meaning |
|---|---|
| transition element/trænˈsɪʃn ˈelɪmənt/ | A d-block d element that forms one or more stable ions with incomplete d orbitals. |
| d-block/diː blɒk/ | d-block |
| oxidation state/ˌɒksɪˈdeɪʃn steɪt/ | The charge an atom would have if all its bonds were ionic; it tracks oxidation and reduction. |
| catalyst/ˈkætəlɪst/ | A substance that increases a reaction rate without being used up overall. |
| complex ion/ˈkɒmpleks ˈaɪɒn/ | A charged species with a central metal ion bonded to surrounding ligands. |
The colourful middle block
- A transition element 过渡元素 is a d-block d区 element that forms one or more stable ions with incomplete d orbitals.
- Scandium and zinc are d-block but not transition (their stable ions have empty or full d orbitals).
- Transition metals share four special properties.
Transition element property lab
Sort transition-metal evidence by the property it shows.
A transition element is a d-block element that:
Difficulty 1/5 · 100 coins + a small bonus on first completion today
The incomplete d orbitals (in a stable ion) define a transition element.
Why are scandium and zinc not classed as transition elements?
Difficulty 1/5 · 100 coins + a small bonus on first completion today
Sc³⁺ has an empty d sub-shell and Zn²⁺ a full one, so neither has incomplete d orbitals in its stable ion.
A transition element forms at least one ion with an incomplete ______ subshell.
Difficulty 1/5 · 100 coins + a small bonus on first completion today
This gives variable oxidation states and colour.
Four key properties (and why)
| Property | Reason |
|---|---|
| variable oxidation state 氧化态 | the 3d and 4s sub-shells are close in energy |
| act as a catalyst 催化剂 | more than one oxidation state, plus vacant d orbitals |
| form complex ions 配离子 | vacant d orbitals accept lone pairs |
| form coloured compounds | electrons move between split d orbitals |
Six transition-metal solutions, each a different colour: cobalt(II) (red), dichromate (orange), chromate (yellow), nickel(II) (green), copper(II) (blue) and permanganate (violet)
Transition metals show variable oxidation states because:
Difficulty 1/5 · 100 coins + a small bonus on first completion today
Similar energies mean similar small amounts of energy can remove different numbers of electrons.
Transition metal compounds are coloured because:
Difficulty 1/5 · 100 coins + a small bonus on first completion today
Ligands split the d orbitals; absorbing light of the gap energy gives the colour we see.
Match each transition-element fact.
Difficulty 2/5 · 140 coins + a small bonus on first completion today
Each item links the term to its correct meaning.
Why transition metals are special
- They form coloured compounds, act as catalysts, and show variable oxidation states.
- All come from the partly filled d subshell.
A ruby is red because of transition-metal (chromium) ions held in its lattice.
Scandium and zinc are exceptions
- Scandium and zinc are d-block but not classed as transition metals.
- Their ions do not have a partly filled d subshell, so they lack the typical properties.
The four key properties of the transition elements
You've got it
- a transition element forms stable ions with incomplete d orbitals (not Sc or Zn)
- four properties: variable oxidation state (3d/4s close), catalysis, complex ions (accept lone pairs), colour (split d orbitals)