Question

Name each of the following compounds: a. \(\mathrm{SF}_{6}\) b. \(\mathrm{N}_{2} \mathrm{O}_{4}\) c. \(\mathrm{SO}_{2}\)

Short answer

a. Sulfur hexafluoride, b. Dinitrogen tetroxide or nitrogen dioxide, c. Sulfur dioxide

Step-by-step solution

- Naming simple covalent compounds

For simple covalent compounds, use prefixes to denote the number of atoms present. The prefixes are mono- (1), di- (2), tri- (3), tetra- (4), penta- (5), hexa- (6), hepta- (7), octa- (8), nona- (9), deca- (10). The first element in the formula is named first, and the full element name is used if there is only one atom. The second element is named as an anion (root name of the element plus the suffix -ide). If the compound has oxygen and is similar to oxyacids when hydrogen is replaced by a cation, it can also be named according to the corresponding acid with a fixed cation.

- Naming ef{SF}_{6}

The compound ef{SF}_{6} consists of one sulfur atom and six fluorine atoms. Therefore, it is named sulfur hexafluoride, where 'hexa-' denotes the presence of six fluorine atoms and '-fluoride' indicates that fluorine is the second element.

- Naming ef{N}_{2}ef{O}_{4}

The compound ef{N}_{2}ef{O}_{4} consists of two nitrogen atoms and four oxygen atoms. Normally this compound is known as dinitrogen tetroxide; however, this compound can also exist as two resonance structures of nitrogen dioxide (ef{NO}_{2}), hence it could also be called nitrogen dioxide. Nonetheless, the preferred IUPAC name is dinitrogen tetroxide.

- Naming ef{SO}_{2}

The compound ef{SO}_{2} consists of one sulfur atom and two oxygen atoms. This compound is named sulfur dioxide, where 'di-' indicates the presence of two oxygen atoms and '-oxide' shows that oxygen is the second element.

Key concepts

Covalent Compound Nomenclature

Understanding how to name covalent compounds is an essential skill in chemistry. This process involves identifying the elements in the molecule and counting the number of atoms of each.

To name a covalent compound, start with the first element listed in the formula. If the element has more than one atom in the molecule, we use prefixes such as mono-, di-, tri-, and so on to indicate the exact number. However, the prefix mono- is typically omitted for the first element. Next, the second element's name is modified to end in '-ide,' akin to how we denote anions.

For example, Co_2 is conventionally called carbon dioxide, not monocarbon dioxide. In the case of SF_6, we say sulfur hexafluoride, applying the prefix hexa- for six fluorine atoms. It is crucial for students to familiarize themselves with these prefixes since they play a fundamental role in the accurate naming of covalent compounds.

Chemical Prefixes

Chemical prefixes are essential tools that help us convey the number of atoms of each element present in a molecular compound. Their proper application is central for clear and concise chemical communication.

Here's a list of common prefixes you need to know:

• mono- for one
• di- for two
• tri- for three
• tetra- for four
• penta- for five
• hexa- for six
• hepta- for seven
• octa- for eight
• nona- for nine
• deca- for ten

You will encounter these prefixes when naming covalent compounds—like dinitrogen tetroxide (N_2O_4) which means two nitrogen and four oxygen atoms. It is vital to remember these prefixes and apply them correctly to ensure that the nomenclature of the compounds you come across or create is precise.

Molecular Formulas

The molecular formula of a compound is a representation of the exact number and type of atoms constituting a single molecule of the compound. It is like a recipe that tells you what ingredients and how much of each you need to make a molecule.

The molecular formula is critical because it conveys information about the compound's composition and can be used to deduce the compound’s structure and properties. For instance, SO_2 indicates that a molecule of sulfur dioxide contains one sulfur atom and two oxygen atoms. Molecular formulas are directly linked to the nomenclature; correctly reading and interpreting these formulas is pivotal in naming compounds accurately.

To facilitate a deeper understanding, it is helpful for students to practice by writing out molecular formulas from compound names and vice versa, thereby reinforcing their understanding of both the nomenclature and the composition of covalent compounds.