Problem 93 - Chemistry Matter and Change

Question

Name each molecule. \(\begin{array}{ll}{\text { a. } \mathrm{NF}_{3}} & {\text { c. } \mathrm{SO}_{3}} \\ {\text { b. NO }} & {\text { d. SiF }_{4}}\end{array}\)

Step-by-Step Solution

Answer

The names of the given molecules are as follows: a. Nitrogen Trifluoride (\(\mathrm{NF}_{3}\)) b. Nitrogen Monoxide (NO) c. Sulfur Trioxide (\(\mathrm{SO}_{3}\)) d. Silicon Tetrafluoride (\(\mathrm{SiF}_{4}\))

Step 1: 1. Identifying elements in the molecule#a. NF3#

For the first molecule, \(\mathrm{NF}_{3}\), there are two elements: Nitrogen (N) and Fluorine (F). We now need to determine the number of each element present in the molecule.

Step 2: 1.1 Count the elements in NF3#

The subscript "3" after F indicates that there are 3 fluorine atoms in the molecule. There is no subscript after N, which means there is only one nitrogen atom.

Step 3: 2. Adding prefixes to the elements for NF3#

We use the "mono" prefix for 1 and "tri" for 3. Since there is only one nitrogen atom, it doesn't require a prefix. Fluorine has three atoms, so the prefix "tri" should be added.

Step 4: 3. Combining elements and prefixes to form full name for NF3#

Putting it all together, the name for \(\mathrm{NF}_{3}\) is Nitrogen Trifluoride.

Step 5: 1. Identifying elements in the molecule#b. NO#

For the second molecule, NO, there are two elements: Nitrogen (N) and Oxygen (O).

Step 6: 1.1 Count the elements in NO#

There is no subscript after N or O, meaning there's only one atom of each element in the molecule.

Step 7: 2. Adding prefixes to the elements for NO#

Since there is only one atom of each element, the "mono" prefix will be used for each. However, when naming binary molecular compounds, the "mono" prefix is typically omitted for the first element.

Step 8: 3. Combining elements and prefixes to form full name for NO#

Putting it all together, the name for NO is Nitrogen Monoxide.

Step 9: 1. Identifying elements in the molecule#c. SO3#

For the third molecule, \(\mathrm{SO}_{3}\), there are two elements: Sulfur (S) and Oxygen (O).

Step 10: 1.1 Count the elements in SO3#

The subscript "3" after O indicates that there are 3 oxygen atoms in the molecule. There is no subscript after S, which means there is only one sulfur atom.

Step 11: 2. Adding prefixes to the elements for SO3#

We use the "mono" prefix for 1 and "tri" for 3. Since there is only one sulfur atom, it doesn't require a prefix. Oxygen has three atoms, so the prefix "tri" should be added.

Step 12: 3. Combining elements and prefixes to form full name for SO3#

Putting it all together, the name for \(\mathrm{SO}_{3}\) is Sulfur Trioxide.

Step 13: 1. Identifying elements in the molecule#d. SiF4#

For the fourth molecule, \(\mathrm{SiF}_{4}\), there are two elements: Silicon (Si) and Fluorine (F).

Step 14: 1.1 Count the elements in SiF4#

The subscript "4" after F indicates that there are 4 fluorine atoms in the molecule. There is no subscript after Si, which means there is only one silicon atom.

Step 15: 2. Adding prefixes to the elements for SiF4#

We use the "mono" prefix for 1 and "tetra" for 4. Since there is only one silicon atom, it doesn't require a prefix. Fluorine has four atoms, so the prefix "tetra" should be added.

Step 16: 3. Combining elements and prefixes to form full name for SiF4#

Putting it all together, the name for \(\mathrm{SiF}_{4}\) is Silicon Tetrafluoride.

Key Concepts

Molecular Compounds

Molecular compounds are composed of molecules formed by atoms of two or more different non-metal elements bonded together. Unlike ionic compounds, which consist of metals and non-metals forming charged ions, molecular compounds are formed by sharing electrons between non-metal atoms. This leads to the creation of covalent bonds. Understanding molecular compounds involves recognizing the elements present and their specific combinations.

• Molecular compounds consist solely of non-metals.
• They are characterized by having covalent bonds.
• Their chemical behavior is inherently different from ionic compounds.

For example, in the molecular compound \(\mathrm{NF}_{3}\), nitrogen and fluorine are both non-metals connected via covalent bonds, resulting in a stable molecule.

Prefixes in Chemistry

Prefixes in chemistry are essential for communicating the number of atoms of each element present in a molecular compound. These prefixes help distinguish different compounds that may have similar compositions. The prefixes commonly used are:

• Mono- for one (often omitted for the first element)
• Di- for two
• Tri- for three
• Tetra- for four
• Penta- for five
• Hexa- for six

Applying these prefixes helps form names that indicate the structure of a molecule, such as "Dinitrogen trioxide" for \(\mathrm{N}_{2}O_{3}\). The systematic use of prefixes enables clear communication amongst chemists about the specific makeup of molecular compounds.

Naming Conventions

Naming conventions for molecular compounds are guided by particular rules to ensure that each compound's name conveys meaningful structural information. This is particularly critical as it helps distinguish between compounds with different properties or compositions. Here are the key guidelines for naming molecular compounds:

• The first element in the formula maintains its elemental name.
• The second element's name is modified to end in "-ide."
• Prefixes are used to denote the number of atoms of each element.
• The "mono-" prefix is typically omitted for the first element.

For instance, the compound \(\mathrm{SiF}_{4}\) is known as "Silicon Tetrafluoride," where "Silicon" refers to the first element and "Tetrafluoride" indicates four fluorine atoms. Mastery of these conventions is essential for anyone involved in the study or application of chemical disciplines.