Which of the following statements describes transition elements? They

Step 1: Analyze the question You are asked to pick the statement that correctly describes transition elements (the d-block elements, e.g. Fe, Cu, Mn, Cr, Ni, Zn-Cu series).

Step 2: Key concept Transition elements have partially filled d-orbitals. Because the 4s and 3d electrons are very close in energy, they can lose different numbers of electrons. This gives rise to these characteristic properties:

• Variable oxidation states (e.g. Fe²⁺ and Fe³⁺, Mn²⁺ to Mn⁷⁺)
• Formation of coloured compounds/ions (e.g. Cu²⁺ is blue, Fe²⁺ is green, Fe³⁺ is yellow-brown)
• Catalytic activity (e.g. Fe in the Haber process, V₂O₅ in the Contact process, MnO₂)
• Formation of complex ions
• Paramagnetism
• High melting points and densities, and they are hard, strong metals

Step 3: Evaluate each option

• A. Very reactive: Wrong. Transition metals are generally much less reactive than Group 1 and 2 metals.
• B. Low melting points: Wrong. They typically have high melting points (e.g. iron melts at about 1538 °C).
• C. Possess variable oxidation state: Correct. This is a hallmark property of transition elements.
• D. Form colourless salts: Wrong. They typically form coloured salts (e.g. CuSO₄ is blue, FeSO₄ is green).

Step 4: Answer

Tip: Remember the transition element "VCC" properties: Variable oxidation states, Coloured compounds, Catalytic activity. If an option says "variable oxidation state," "coloured," or "catalyst," it is probably right. If it says "low melting point" or "colourless," eliminate it.