Covalent Compounds: Structure, Nomenclature, and Properties

Covalent Compounds

Introduction to Covalent Bonding

Covalent bonds are a fundamental type of chemical bond formed by the sharing of electrons between two atoms, typically nonmetals. This sharing allows each atom to achieve a stable electron configuration, often resembling that of noble gases.

• Covalent bond: A chemical bond where two atoms share one or more pairs of electrons.

• Molecule: A discrete group of atoms held together by covalent bonds.

• Example: Two hydrogen atoms share electrons to form a hydrogen molecule (H2), each achieving a stable configuration with two electrons.

Diatomic Elements

Elements That Form Diatomic Molecules

Certain elements naturally exist as diatomic molecules, meaning two atoms of the same element are covalently bonded together.

• Diatomic elements: Hydrogen (H2), Nitrogen (N2), Oxygen (O2), Fluorine (F2), Chlorine (Cl2), Bromine (Br2), Iodine (I2).

• These elements share electrons to form stable, covalent molecules.

Diatomic Molecule	Name
H2	Hydrogen
N2	Nitrogen
O2	Oxygen
F2	Fluorine
Cl2	Chlorine
Br2	Bromine
I2	Iodine

Nomenclature of Covalent Compounds

Rules for Naming Covalent Compounds

Covalent compounds are named using specific rules to indicate the types and numbers of atoms present.

• Name the first nonmetal by its element name.

• Name the second nonmetal using the first syllable of its element name followed by -ide.

• Use prefixes to indicate the number of atoms of each element.

• Prefixes are necessary because two nonmetals can form multiple compounds.

Examples of compounds of N and O:

• NO: Nitrogen monoxide

• N2O: Dinitrogen monoxide

• N2O5: Dinitrogen pentoxide

Prefixes for Covalent Compound Names

Number of Atoms	Prefix
1	Mono
2	Di
3	Tri
4	Tetra
5	Penta
6	Hexa
7	Hepta
8	Octa
9	Nona
10	Deca

Applying Nomenclature Rules

• Omit the prefix "mono-" for the first element if only one atom is present, but retain it for the second element.

• If two vowels would be adjacent, omit the first vowel (e.g., monoxide instead of monooxide).

• Example: CO is named carbon monoxide.

Practice Examples

Compound	Symbols of Elements	Subscripts	Name
P2O5	P, O	2, 5	Diphosphorus pentoxide
CCl4	C, Cl	1, 4	Carbon tetrachloride
Cl2O7	Cl, O	2, 7	Dichlorine heptoxide
NI3	N, I	1, 3	Nitrogen triiodide

Example Practice Problem: The systematic name of ICl3 is iodine trichloride.

*Additional info: These notes cover foundational concepts in GOB Chemistry, including covalent bonding, diatomic elements, and systematic nomenclature, with tables and examples for clarity.*