Which of the following elements exhibits variable oxidation states and forms colored compounds?
- Sodium
- Calcium
- Copper
- Magnesium
The Correct Option is C
Solution and Explanation
In chemistry, the ability of an element to exhibit variable oxidation states and form colored compounds is characteristic of transition metals. Transition metals have electrons in d orbitals, which allow them to have multiple oxidation states and form complex ions with distinct colors.
Examining the options:
- Sodium: An alkali metal with a stable oxidation state of +1. It does not form colored compounds under normal conditions.
- Calcium: An alkaline earth metal with a stable oxidation state of +2, generally forming colorless compounds.
- Copper: A transition metal that exhibits variable oxidation states, commonly +1 and +2. Copper forms colored compounds, such as copper(II) sulfate, which is blue in color.
- Magnesium: An alkaline earth metal with a stable oxidation state of +2, typically forming colorless compounds.
Therefore, the element that exhibits variable oxidation states and forms colored compounds is Copper
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