KEY2CHEM

Structure of Covalent Network Solids

Covalent network solids consist of nonmetals (either elements or compounds) covalently bonded together into a two-dimensional or three-dimensional network. Strong covalent bonds connect the atoms in the solids, so covalent network solids often have high melting points. Often, elements of the carbon family form covalent network solids due to their ability to form four bonds. 


Example 1.

 

______ is an allotrope of carbon.

A. Graphite

B. Silicon

C. Brass

 

 

Solution 

 

A. Graphite

An allotrope is a particular physical form of an element. Allotropes of carbon include graphite and diamond.


Example 2.

 

What is true about covalent network solids?

A. They have high melting points due to the strong ionic bonds holding the ions together.

B. They consist of covalently-bonded two-dimensional or three-dimensional structures.

C. They have delocalized electrons surrounding positively charged metal cores.

 

 

 

Solution

B. They consist of covalently-bonded two-dimensional or three-dimensional structures.

Covalent network solids consist of nonmetals covalently bonded together to form two-dimensional or three-dimensional structures.

 

 

Example 3.

 

Covalent network solids consist of _______ connected by ______ bonds.

A. nonmetals, ionic

B. nonmetals, covalent

C. metals, ionic

 

 

Solution

 

B. nonmetals, covalent

Covalent network solids consist of nonmetals connected by covalent bonds.