Problem 57 - Chemistry and Chemical Reactivity

Question

Name each of the following binary, nonionic compounds: (a) \(\mathrm{NF}_{3}\) (b) HI (c) \(\mathrm{BI}_{3}\) (d) \(\mathrm{PF}_{5}\)

Step-by-Step Solution

Answer

(a) Nitrogen trifluoride, (b) Hydrogen iodide, (c) Boron triiodide, (d) Phosphorus pentafluoride.

Step 1: Review Naming Rules for Binary Compounds

Binary compounds consist of two different elements. For binary nonionic compounds composed of nonmetals, we use prefixes to indicate the number of each type of atom: 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. The first element keeps its name, and the second element ends with the suffix -ide.

Step 2: Name \\(\mathrm{NF}_{3}\\)

\(\mathrm{N}\) is nitrogen and \(\mathrm{F}\) is fluorine. The prefix for three fluorine atoms is "tri." Therefore, the compound is named nitrogen trifluoride.

Step 3: Name HI

\(\mathrm{H}\) is hydrogen and \(\mathrm{I}\) is iodine. As a binary compound, it's named hydrogen iodide. Note that 'mono' is not used at the beginning.

Step 4: Name \\(\mathrm{BI}_{3}\\)

\(\mathrm{B}\) is boron and \(\mathrm{I}\) is iodine. The prefix for three iodines is "tri," so the compound is called boron triiodide.

Step 5: Name \\(\mathrm{PF}_{5}\\)

\(\mathrm{P}\) is phosphorus and \(\mathrm{F}\) is fluorine. The prefix for five fluorines is "penta." The name is phosphorus pentafluoride.

Key Concepts

Binary Compounds

Binary compounds are fascinating because they represent the simplest form of chemical compounds, consisting of just two different elements. Imagine two unique building blocks coming together to create something new. These compounds can be either ionic or covalent, depending on how the atoms share or transfer electrons. Typically, binary compounds involve a combination of a metal and a nonmetal in ionic compounds, while non-metals form binary covalent compounds, like the examples in this exercise. Understanding the basics offers insight into their naming and characteristics:

• Binary Ionic Compounds: Involve transferring electrons, resulting in positively and negatively charged ions. Commonly formed between metals and non-metals.
• Binary Covalent Compounds: Involve sharing electrons. This is where non-metals pair up to form a molecular compound like \(\mathrm{NF}_{3}\).

By learning how binary compounds form and are named, students can better understand how matter is organized at the molecular level.

Chemical Naming Rules

Mastering the naming rules for binary compounds is like learning a new language. It’s a structured system that ensures chemists worldwide can communicate effectively.For binary covalent compounds, which are the focus of this exercise, the rules are straightforward yet crucial:

• The first element in the formula is named first and retains its elemental name. Example: In \(\mathrm{NF}_{3}\), the first element is nitrogen.
• The second element's name is modified to end in -ide. Example: Fluorine becomes fluoride.
• Numerical prefixes denote the number of atoms present; except "mono", which is generally omitted for the first element. Examples: "tri" for three fluorine atoms in \(\mathrm{NF}_{3}\), leading to the name "nitrogen trifluoride".

These rules might seem simple, but they are vital for correctly identifying compounds and understanding their properties. By following these guidelines, the chemical name provides more than just identification—it reveals the compound's composition.

Nonionic Compounds

Nonionic compounds, or covalent compounds, result from the sharing rather than the transfer of electrons between atoms. In nonionic binary compounds, the focus is on covalent bonding, where atoms share electrons to achieve a stable electron configuration.Key traits of nonionic (covalent) compounds include:

• Formation between two nonmetals. This is seen in compounds like \(\mathrm{NF}_{3}\) and \(\mathrm{PF}_{5}\).
• Low melting and boiling points compared to ionic compounds, due to weaker forces between molecules.
• Often gases or liquids at room temperature.

The concept of nonionic compounds highlights the diversity of chemical bonding and the intricate way atoms interact to form stable substances. Understanding these interactions leads to a deeper appreciation of the molecular world and the complexity behind even the simplest compounds.