Question

${}^{28}Si\text{ and }{}^{29}Si$ are known as what?

Answer 1

Hint :The superscript number to the left of the element abbreviation indicates the number of protons plus neutrons and one proton. This is approximately twice the mass of protium where tritium has approximately three times the mass of protium.

Complete Step By Step Answer:
Silicon is a semiconductor, meaning that it can conduct electricity only in certain conditions and act as insulator under others
Isotopes are atoms of the same elements that have different numbers of neutrons but the same number of protons and electrons. The difference in the number of neutrons between the various isotopes of an element which exists in nature implies that the various isotopes have different types of masses.
Silicon is the second most abundant element on earth, with three major stable isotopes. ${}^{28}Si,{}^{29}\text{Si and }{}^{30}Si$ , with abundances of $99.22$ , $4.68$ and $3.08\mathrm{\%}$ respectively. Silicon is believed to be a cosmic product of alpha particle absorption, at a temperature of about $10$ K, by the nuclei of carbon $12$ , oxygen $16$ and neon $20$ . The energy binding the particles that form the nucleus of silicon is about $8.4$ million electron volts per nucleon. In the electronics industry, silicone plays a huge role.

Note :
Silicon is a semiconductor, meaning that it can conduct electricity only in certain conditions and act as an insulator under others. These characteristics make it an ideal material for making transistors that amplify electrical signals. Coatings for electrical products, such as keypads, keyboards and copier rollers, as well as the hard coatings for computers, facsimile machines, telephones and home entertainment equipment are all made from silicone.