Question

Name each molecular compound. (a) \(\mathrm{SO}_{2}\) (b) \(\mathrm{NI}_{3}\) (c) \(\mathrm{BrF}_{5}\) (d) NO (e) \(\mathrm{N}_{4} \mathrm{Se}_{4}\)

Short answer

The names of the molecular compounds are: (a) sulfur dioxide, (b) nitrogen triiodide, (c) bromine pentafluoride, (d) nitrogen monoxide, (e) tetranitrogen tetrarselenide.

Step-by-step solution

Understanding the Prefix System

In naming molecular compounds, prefixes are used to denote the number of atoms of each element present in the compound. The prefixes are: 1 - mono (omitted for the first element), 2 - di, 3 - tri, 4 - tetra, 5 - penta, 6 - hexa, 7 - hepta, 8 - octa, 9 - nona, 10 - deca.

Naming SO2

Sulfur dioxide comprises one sulfur atom and two oxygen atoms. The prefix for one is omitted for sulfur, and 'di' for two is used with oxygen, forming 'sulfur dioxide'.

Naming NI3

Nitrogen triiodide consists of one nitrogen atom and three iodine atoms. The prefix 'tri' for three is used with iodine, forming 'nitrogen triiodide'.

Naming BrF5

Bromine pentafluoride has one bromine atom and five fluorine atoms. The prefix 'penta' for five is used with fluorine, forming 'bromine pentafluoride'.

Naming NO

Nitrogen monoxide consists of one nitrogen atom and one oxygen atom. Since there is only one oxygen atom, we use the prefix 'mono' and get 'nitrogen monoxide'. Remember, the prefix 'mono' is not used for nitrogen here because it's the first element listed.

Naming N4Se4

Tetranitrogen tetrarselenide is composed of four nitrogen atoms and four selenium atoms. The prefix 'tetra' for four is used for both elements, forming 'tetranitrogen tetrarselenide'. Note that even though nitrogen is the first element, since it has a prefix other than 'mono', the prefix is used.

Key concepts

Chemical Nomenclature

Chemical nomenclature is the standardized process used for naming chemical compounds, ensuring that each compound has a unique and universally understood name. This system allows scientists and students alike to communicate about chemical substances without ambiguity.

The International Union of Pure and Applied Chemistry (IUPAC) provides the guidelines for naming compounds, which includes organic, inorganic, and polyatomic ions. The nomenclature rules differ depending on the type of compound, such as ionic, molecular (covalent), or acid.

Exercise Improvement Advice for Chemical Nomenclature:

To enhance understanding, it's important to reinforce the concept by practicing various examples of chemical compounds. Additionally, engaging with interactive nomenclature tools or quizzes can help solidify the learning process. Comparing and contrasting similar compounds with slight differences in composition can aid in grasping the importance of the nomenclature rules.

Prefix System in Chemistry

The prefix system in chemistry is part of the chemical nomenclature used specifically for naming molecular (covalent) compounds. It involves adding prefixes to the names of elements to indicate the number of atoms of each present in the compound.

The prefixes are derived from Greek or Latin numbers and are as follows: '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, and 'deca-' for ten. Notably, 'mono-' is typically omitted for the first element in the compound if it's present in a single quantity.

Exercise Improvement Advice:

When learning the prefix system, memorization through repetition can be beneficial. Creating mnemonic devices can also assist in remembering the prefixes. Practice by writing out the name and molecular formula of various compounds. Understanding that there is a systematic approach to naming enables students to decipher complex names and makes the learning process easier.

Molecular Compound Names

Molecular compounds, sometimes referred to as covalent compounds, consist of atoms bonded together by shared electrons. The naming of these compounds follows a simple set of rules that involves using the prefix system in combination with the names of the elements.

The first element in the formula retains its elemental name, while the second element has an '-ide' suffix added to the root of its name. The appropriate numerical prefix is added to each element if there is more than one atom of that element present. Exceptionally, the prefix 'mono-' is typically omitted from the first element.

Exercise Improvement Advice:

To improve your ability in naming molecular compounds, start by writing down several compounds and their formulas, then naming each according to the rules. The more you practice, the more familiar you will become with the variations and exceptions. Use flashcards to help memorize the different prefixes and their associated numbers, and try naming compounds in different orders to test your understanding of when to use the prefix 'mono-'.