(a) What is the atomic number of carbon? Write its electronic configuration.
(b) What type of chemical bonds are formed by carbons? Why?
(c) Name the three allotropic forms of carbon.

Hint: The number of protons present in the nucleus of an atom is known as its atomic number. The arrangement of electrons in the outer shells of an atom is known as its electronic configuration. And the different structural forms of an element are known as its allotropes.

Complete step by step answer:
(a)
Atomic number: The number of protons present in the nucleus of an atom which belongs from an element is known as its atomic number.
And we all know that a carbon atom has a proton in its nucleus therefore the atomic number of carbon is 6.
Electronic configuration: The Systematic arrangement or distribution of electrons of an atom into its atomic orbitals is known as electronic configuration.
The electronic configuration of carbon atom is as follows: $ 2,4 $
As the carbon atom requires four more electrons to complete its outermost octet, therefore its valency is 4 (four).
(b)
Covalent bonds are formed by the carbon atoms. (Covalent bond: The bond in which sharing of electrons takes place during its formation is known as covalent bond.)
Carbon atoms form covalent bonds because its valency is four and it can only complete its octet by sharing electrons.
(c)
Allotropes: The existing different structural forms of the same element are known as its allotropes.
Carbon has three allotropic forms and these are as follows: Diamond, buckminsterfullerene and graphite.

Note:
Allotropes of carbon have a wide range of uses. Diamond is used in cutting, drilling and as jewellery in our daily lives. Graphite is an electrical conductor. Diamond is the hardest substance on the earth.