Question

Write the name and symbol of the following elements.
The metalloid in the third period: ___________.

Answer 1

Hint: The elements whose properties are intermediate between metals and nonmetals are called metalloids. In the modern periodic table, there are a total 7 metalloids which are arranged diagonally in p-block.
Complete step by step answer:
 In the modern form of periodic table, total 7 elements are found whose properties are intermediate between metals and nonmetals. These are called metalloids.

So, we have metalloids - Boron (B), Silicon (Si), Germanium (Ge), Arsenic (As), Antimony (Sb), Tellurium (Te) and Astatine (At).
Out of these, Silicon is a metalloid in the third period.
Silicon belongs to the third period, 14^th group. The elements in this group are also known as Carbon family. Atomic number of Silicon is 14 and its electronic configuration is $$\text{1}{\text{s}}^2\text{ 2}{\text{s}}^2\text{ 2}{\text{p}}^6\text{ 3}{\text{s}}^2\text{ 3}{\text{p}}^2$$.
Additional information: Metalloids generally have metallic appearance but they are brittle. Their chemical properties show close similarity with non-metals. Metalloids are mostly used as alloys, biological agents and catalysts. They are of extreme use in semiconductors and electronics. In the modern periodic table, metalloids lie on either side of the line dividing metals from nonmetals.
Silicon is a brittle, crystalline solid with a bluish grey metallic lustre. It rarely occurs in its purest form in earth’s crust. It is mostly found as dust, sand and clay. In these forms, it is used in construction works. Cast iron contains silicon. Silicon is also widely used in making semiconductors and in production of fire bricks.

Note: Total 7 metalloids are found in the modern periodic table, out of this, Silicon is from the third period. Silicon has tremendous uses, especially in semiconductors.