Question

What is meant by tetravalency and catenation?

Answer 1

Tetravalency

Each carbon ($C$) atom usually forms four covalent bonds. Thus, a Carbon ($C$) atom can connect to a many as four other atoms. Since it can neither lose nor gain electrons to achieve octet, it forms covalent bonds by sharing its four electrons with other atoms. This tendency is known as tetravalency of Carbon ($C$).

Catenation

The Carbon ($C$) atom has a unique ability to link successively to other Carbon ($C$) atoms to form chains of varying lengths and shapes. It is called catenation.