Question

Which of the following elements exhibits variable oxidation states and forms colored compounds?

• A. Sodium
• B. Calcium
• C. Copper
• D. Magnesium

Answer 1

The Correct Option is C

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