Ionic and Covalent Bonding & Naming Covalent Compounds

Chemical Bonding

Types of Chemical Bonds

Chemical bonds are the forces that hold atoms together in compounds. The two main types of chemical bonds are ionic bonds and covalent bonds. Understanding the differences between these bonds is fundamental in chemistry.

• Ionic Bonding: Involves the transfer of electrons from one atom (typically a metal) to another (typically a nonmetal), resulting in the formation of oppositely charged ions that attract each other.

• Covalent Bonding: Involves the sharing of electrons between two nonmetal atoms, resulting in the formation of a molecule.

Example:

• Ionic Bond: $\text{Mg}^{2+}$ and $\text{F}^-$ combine to form $\text{MgF}_2$.

• Covalent Bond: Two nonmetals, such as hydrogen and oxygen, share electrons to form $\text{H}_2\text{O}$.

Naming Covalent (Molecular) Compounds

Prefix (IUPAC) System for Naming Molecular Compounds

Covalent compounds are named using prefixes to indicate the number of each type of atom present in the molecule. This system is necessary because, unlike ionic compounds, covalent compounds do not contain ions or charges to indicate their composition.

Number	Prefix
1	mono-
2	di-
3	tri-
4	tetra-
5	penta-
6	hexa-
7	hepta-
8	octa-
9	nona-
10	deca-

Steps for Naming Molecular Compounds

1. Name the first nonmetal by its element name.

2. Name the second nonmetal by using the root of its element name and adding the suffix -ide.

3. Add prefixes to indicate the number of atoms of each element present in the molecule. The prefix 'mono-' is usually omitted for the first element.

Examples:

• $\text{CCl}_4$: Carbon tetrachloride

• $\text{CO}$: Carbon monoxide

• $\text{P}_4\text{O}_{10}$: Tetraphosphorus decoxide

• $\text{SF}_6$: Sulfur hexafluoride

• $\text{C}_6\text{H}_{14}$: Pentacarbon decahydride

Writing Formulas from Names

• Nitrogen tribromide: $\text{NBr}_3$

• Oxygen difluoride: $\text{OF}_2$

• Trisulfur decaiodide: $\text{S}_3\text{I}_{10}$

• Hexafluoro nonasulfide: $\text{F}_6\text{S}_9$

Diatomic Elements

Definition and Examples

Some elements are more stable as molecules consisting of two atoms of the same element bonded together. These are called diatomic elements. Any element whose name ends in '-gen' and the halogens (Group 17) are diatomic in their natural state.

• Nitrogen: $\text{N}_2$

• Oxygen: $\text{O}_2$

• Hydrogen: $\text{H}_2$

• Halogens: $\text{F}_2$, $\text{Cl}_2$, $\text{Br}_2$, $\text{I}_2$

Additional info: Diatomic elements are important in both chemical reactions and in understanding the natural forms of elements.