Which of the following elements is a metalloid?

Step 1: Analyze the question We need to identify which element is a metalloid, meaning an element with properties between those of metals and non-metals.

Step 2: The concept Metalloids (semi-metals) have a metallic appearance but are brittle, and they are usually semiconductors. The common metalloids are:

• Boron (B)
• Silicon (Si)
• Germanium (Ge)
• Arsenic (As)
• Antimony (Sb)
• Tellurium (Te)

Step 3: Check each option

• A. Carbon: a non-metal. (Graphite conducts electricity, but carbon is still classed as a non-metal.)
• B. Oxygen: a non-metal gas.
• C. Silicon: a metalloid. It has a shiny, metallic look, is brittle, and is a semiconductor, which is why it is used in computer chips and solar cells.
• D. Sodium: a reactive alkali metal.

Step 4: Answer The correct option is **C.

Tip: Picture the "staircase" on the periodic table running from boron down to tellurium. The elements along that staircase are the metalloids. A quick way to remember the key ones is B, Si, Ge, As, Sb, Te. In WASSCE, when you see silicon, think "semiconductor", which signals a metalloid.