Question

What is the maximum number of covalent bonds?

Answer 1

Covalent compounds formed by sharing of electrons between their atoms. Covalent bonds form by the help of valence shell electrons. The covalent bond depends upon the number of valence shell electrons.

Complete answer:
Covalent bond is formed when sharing of electrons takes place between two atoms. For the formation of covalent bonds, valence electrons are required. So, for the maximum number of covalent bonds, we have to check the maximum number of valence shell electrons. In noble gas there is a maximum number of valence electrons, i.e. eight electrons. Which means it can form $8$ covalent bonds. But noble gases rarely form bonds; they are very inactive because they are stable and have electronegativity of almost zero.
Metals in the group second can form many covalent bonds such as copper that have the possibility of forming $11$ covalent bonds as it contains $11$ valence electrons, i.e. $2\;4s$ and $9\;3d$ . But we all know that metals tend to form ionic bonds not covalent bonds.
After these two group elements, halogen has a maximum number of valence electrons. It has seven valence electrons. Thus, it can make seven covalent bonds. For example, $ClO_4^{1 - }$ have seven covalent bonds. Chlorine in $ClO_4^{1 - }$ has seven covalent bonds that share electrons with four oxygen atoms. Out of four, three oxygen atoms form double bonds with chlorine whereas one oxygen atom forms a single bond with chlorine atom.
Thus the maximum number of covalent bonds is seven.

Note:
Due to the sharing of electrons, the covalent bond is the strongest bond. It breaks with the help of enzymes. Covalent bonds form between two atoms when one of them cannot easily have a noble gas configuration even through gaining or losing electrons.