Where does this come from, and can I check it?

Copper sulfate is blue because its d electrons absorb part of the visible spectrum. The figure is taken from Royal Society of Chemistry, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.

Is this really a science fact?

Yes. It sits on the Science shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.

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The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.

Mondo Knows Facts

Transition metals form brightly coloured compounds

Copper sulfate is blue because its d electrons absorb part of the visible spectrum In these compounds, electrons in partly filled d orbitals jump between energy levels split by the surrounding ligands. The size of that gap decides which wavelengths are absorbed and which reach the eye. Changing the ligand or the oxidation state shifts the colour, which is why manganese compounds range from pale pink to deep purple. It sits in Mondo's science collection, one of 200 facts that each trace back to the reference below.

Where this comes from

Royal Society of Chemistry

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Tags: chemistry, colour, metals

Transition metals form brightly coloured compounds: the short answers

Where does this come from, and can I check it?: Copper sulfate is blue because its d electrons absorb part of the visible spectrum. The figure is taken from Royal Society of Chemistry, which is linked in full on this page. Every fact on Mondo Knows names its source rather than repeating an unsourced claim.
Is this really a science fact?: Yes. It sits on the Science shelf, one of 2,600 sourced facts grouped into space, animals, the human body, history, science and more. Category pages collect every fact in the same field.
What else can I read about it?: The links under the fact point to a quiz, game, puzzle or calculator on the same subject, and the shelf below shows related facts. The wording here is original, and quoted phrases are marked as quotations.