Solution:Concept- A metalloid is a chemical element with characteristics that fall between metals and nonmetals. Metals are found on the left-hand side of the periodic table, while non-metals are present on the right-hand side. Silicon is a metalloid, sodium is a metal, and chlorine is a non-metal in the provided issue. Metals are elements that have the ability to release electrons.
Sodium has an atomic number of 11. As a result, it has an electrical configuration of 2,8,1. As a result, the outermost orbit has only one electron. As a result, it will lose one electron to achieve a noble gas state, whereas chlorine has an atomic number of 17 and an electronic configuration of 2,8,7. As a result, it will gain one electron in order to achieve a noble gas configuration. As a result, it is non-metal. Silicon has an atomic number of 14 and an electrical configuration of 2,8,4. Chemically, it does not lose or acquire four electrons; rather, it shares four electrons with other elements. Physically, silicon is a metalloid with fewer electrons yet is brittle in nature. It is a metalloid because its qualities are between metal and non-metal.
Thus, out of sodium, chlorine, and silicon; silicon is a metalloid.
Hence, option 3 is correct.