Question

Name each of the following: a. \(\mathrm{CS}_{2}\) b. \(\mathrm{P}_{2} \mathrm{O}_{5}\) c. \(\mathrm{Cl}_{2} \mathrm{O}\) d. \(\mathrm{PCl}_{3}\) e. \(\mathrm{CO}\)

Short answer

a. Carbon disulfide, b. Diphosphorus pentoxide, c. Dichlorine monoxide, d. Phosphorus trichloride, e. Carbon monoxide.

Step-by-step solution

Name \(\text{CS}_2\)

The compound \(\text{CS}_2\) has one carbon (C) and two sulfur (S) atoms. This is commonly known as carbon disulfide.

Name \(\text{P}_2 \text{O}_5\)

The compound \(\text{P}_2 \text{O}_5\) has two phosphorus (P) and five oxygen (O) atoms. It is named diphosphorus pentoxide.

Name \(\text{Cl}_2 \text{O}\)

The compound \(\text{Cl}_2 \text{O}\) includes two chlorine (Cl) atoms and one oxygen (O) atom. This is known as dichlorine monoxide.

Name \(\text{PCl}_3\)

The compound \(\text{PCl}_3\) has one phosphorus (P) and three chlorine (Cl) atoms. It is called phosphorus trichloride.

Name \(\text{CO}\)

The compound \(\text{CO}\) consists of one carbon (C) and one oxygen (O) atom. This is commonly known as carbon monoxide.

Key concepts

chemical nomenclature

Chemical nomenclature is the system used for naming chemical substances. It provides a standardized way to communicate the names and formulas of compounds clearly. Correct chemical nomenclature helps avoid confusion in scientific communication.
Chemical names can tell you about the elements in a compound and their relative amounts. For example, carbon monoxide (CO) indicates that the compound contains one carbon atom and one oxygen atom.
The naming rules for compounds depend on the types of elements they contain. There are different systems for naming ionic, covalent (molecular), and organic compounds.

binary compounds

Binary compounds are composed of two different elements. The elements can be either metals or non-metals.
When we name binary compounds, the element on the left (usually a metal or less electronegative non-metal) is named first. The second element's name is altered to end in '-ide'. For example, in sodium chloride (NaCl), 'sodium' is the metal, and 'chloride' is the modified name of chlorine.
Covalent binary compounds, which are formed between two non-metals, use a different naming system. They include prefixes to indicate the number of each type of atom present in the molecule.

molecular compounds

Molecular compounds consist of two or more non-metals. These compounds share electrons to form covalent bonds.
When naming molecular compounds, we use prefixes to indicate the number of each type of atom. For example, \(\text{P}_2 \text{O}_5\) is named diphosphorus pentoxide, where 'di-' means two, and 'penta-' means five. This tells us there are two phosphorus atoms and five oxygen atoms in the compound.
The second element in the compound's name ends in '-ide,' just like with binary compounds. So, \(\text{CO}\) is called carbon monoxide. 'Mono-' means one, indicating there is one oxygen atom.

prefixes in naming compounds

Prefixes are used in naming molecular compounds to indicate the number of atoms of each element present in the compound. Here are the most common prefixes:

• 1: Mono- (often omitted for the first element)
• 2: Di-
• 3: Tri-
• 4: Tetra-
• 5: Penta-
• 6: Hexa-
• 7: Hepta-
• 8: Octa-
• 9: Nona-
• 10: Deca-

For example, \(\text{Cl}_2 \text{O}\) is named dichlorine monoxide, where 'di-' indicates two chlorine atoms, and 'mono-' indicates one oxygen atom. Similarly, \(\text{PCl}_3\) is phosphorus trichloride, with 'tri-' indicating three chlorine atoms.
Remember that the prefix 'mono-' is often skipped for the first element when there is only one atom of that element.