Chemistry · Periodic Classification Of Properties · NEET
NCERT names exactly 5 metalloids: Silicon (Si), Germanium (Ge), Arsenic (As), Antimony (Sb) and Tellurium (Te). These are the elements that border the zig-zag line and run diagonally across the periodic table. For NEET, learn this exact list, because that is what the exam checks.
The zig-zag line (also called the staircase or diagonal line) is a thick stepped line drawn in the p-block. It separates metals (on the left) from non-metals (on the right). NCERT says the change from metallic to non-metallic character is NOT sudden, so the line is drawn in a zig-zag shape. The elements that lie right along this line are the metalloids.
Neither fully. A metalloid shows some properties of metals and some of non-metals at the same time. For example, silicon looks shiny like a metal but is brittle like a non-metal, and it conducts electricity only a little (it is a semiconductor). This 'in-between' nature is exactly why they are also called semi-metals.
Silicon is a metalloid. Students often think it is a non-metal because it is in the same group (14) as carbon, but silicon sits ON the zig-zag line, so it behaves as a metalloid. This makes it a semiconductor, which is why it is used in computer chips.
They are found only in the p-block, along the diagonal zig-zag line, mostly in groups 13 to 16. Metals are to the left of the line, non-metals to the right, and metalloids sit on the border. There are NO metalloids in the s-block, d-block or f-block.
Many textbooks list boron (B) as a metalloid too, and it does behave like one. But the NCERT Class 11 chapter (3.6.5) names only Si, Ge, As, Sb and Te as examples. For NEET, if a question is based on NCERT, use these 5. If a question separately asks about boron's semi-metal behaviour, treat it as a metalloid as well.
Only partly. Metals conduct well, non-metals do not conduct, and metalloids conduct a little bit. This half-way conduction is called semiconduction. That is the key clue that an element is a metalloid, and it is often the point NEET tests.
The correct order of increasing metallic character of Na, Be, P, Mg and Si is:
Try the real previous-year questions from this chapter — each with the answer and a full solution.
NCERT names 5 metalloids: Si, Ge, As, Sb and Te. Some broader lists add boron, but the Class 11 chapter uses these five examples.
Because the change from metal to non-metal is gradual, not sudden. A straight line would wrongly suggest a sharp cut. The zig-zag (staircase) shape shows the smooth, step-by-step change and lets the metalloids sit exactly on the border.
Semi-metals. Both names mean the same thing: elements with mixed metal and non-metal properties.
Yes. All metalloids lie along the zig-zag line, which passes only through the p-block. There are no metalloids in the s, d or f blocks.
Questions often mix up metals, non-metals and metalloids, or ask you to place an element like silicon or arsenic. Knowing the 5 NCERT metalloids and the zig-zag line lets you answer these quickly and avoid the group-based trap.
