Identify the metalloid among the following elements based on its intermediate metallic and non metallic properties.

Introduction / Context:
In the periodic table, elements are broadly categorised as metals, non metals and metalloids. Metalloids display properties intermediate between those of metals and non metals and are especially important in semiconductor technology and materials science. This question asks you to pick the metalloid from a short list of elements, testing your knowledge of periodic table classifications and the characteristic behaviour of these elements.

Given Data / Assumptions:

• Silicon is in group 14 in the periodic table.
• Sulphur is a typical non metal in group 16.
• Scandium is a transition metal in group 3.
• We are using the commonly accepted list of metalloids used in school level chemistry.

Concept / Approach:
Metalloids are elements that are often found along the zigzag boundary between metals and non metals on a periodic table. Classic examples include boron, silicon, germanium, arsenic, antimony and tellurium. They usually have a metallic appearance but are brittle and behave as semiconductors rather than good conductors. Silicon, in particular, is the best known metalloid and is widely used in computer chips and solar cells. Sulphur, on the other hand, is a yellow brittle non metal, and scandium is a metallic element used in alloys. Therefore, among the listed elements, only silicon fits the metalloid category.

Step-by-Step Solution:
Step 1: Recall the standard examples of metalloids: boron, silicon, germanium, arsenic, antimony and tellurium. Step 2: Identify silicon from the list as one of these standard metalloids, positioned along the metalloid staircase in group 14. Step 3: Consider sulphur. It is a typical non metal with low electrical conductivity and forms acidic oxides. It is not usually classified as a metalloid. Step 4: Consider scandium. This element is located in the transition metal block, is metallic in nature and is not part of the metalloid group. Step 5: Because only silicon belongs to the recognised metalloid set, options all of the above and none of the above are incorrect.

Verification / Alternative check:
A quick look at a colour coded periodic table confirms that silicon is often highlighted as a metalloid or semimetal, while sulphur is coloured as a non metal and scandium as a metal. Their uses also agree with these classifications. Silicon is used extensively in semiconductors and solar cells, leveraging its intermediate conductivity. Sulphur is used in sulphuric acid production and as a fungicide, reflecting typical non metal chemistry. Scandium is employed in aluminium alloys and lighting, consistent with metallic properties. These real world roles reinforce the classification of silicon as the metalloid in the list.

Why Other Options Are Wrong:
- Sulphur: This is a non metal with properties such as low electrical conductivity and high electronegativity, not a metalloid.
- Scandium: A transition metal, metallic in appearance and behaviour, not intermediate between metals and non metals.
- All of the above: This would require every listed element to be a metalloid, which conflicts with standard periodic table classifications.
- None of the above: This would imply that no metalloid is present in the list, which is incorrect because silicon is a classic metalloid.

Common Pitfalls:
Students sometimes broadly label any element that is not clearly metallic as a metalloid, but the category is restricted to a specific set of elements near the metal non metal boundary. Confusion also arises because different textbooks sometimes list slightly different sets of metalloids. However, silicon consistently appears in every list. Remembering that silicon sits just below carbon and next to aluminium and is heavily used in electronics can help fix its metalloid status firmly in memory.

Final Answer:
The metalloid in the list is Silicon.