section 4.2 ways to achieve stability (cont.) atoms can also share valence electrons to achieve a...

Section 4.2

Ways to Achieve Stability (cont.)

• Atoms can also share valence electrons to achieve a stable octet.

Section 4.2

Ways to Achieve Stability (cont.)

• The attraction of two atoms for a shared pair of electrons is called a covalent bond.

• A compound whose atoms are held together by covalent bonds is a covalent compound.

• A molecule is an uncharged group of two or more atoms held together by covalent bonds.

Section 4.2

Ways to Achieve Stability (cont.)

• Two nonmetallic elements usually achieve stability by sharing electrons to form a covalent compound.

• If the reacting atoms are a metal and a nonmetal, they are much more likely to transfer electrons and form an ionic bond.

Section 4.2

Ways to Achieve Stability (cont.)

• In addition to double bonds, atoms can form triple bonds.

Section 4.2

How do ionic and covalent compounds compare? (cont.)

• Interparticle forces, or the forces between particles that make up a substance, are the key to determining the state of matter of a substance.

• The difference in strength of the interparticle forces in covalent compounds compared to ionic compounds explains differences in their properties.

Section 5.2

Properties of Covalent Compounds (cont.)

• Distillation is the method of separating substances in a mixture by the evaporation of a liquid and subsequent condensation of its vapor.

• Most covalent compounds are not electrolytes because they do not easily form ions.

Section 5.2

• A molecule that forms when atoms of the same element bond together is called a molecular element.

Molecular Elements

Section 5.2

• Seven nonmetal elements are found naturally as diatomic elements, or molecular elements of two identical atoms.

– hydrogen

– nitrogen

– oxygen

– fluorine

Molecular Elements (cont.)

– chlorine

– bromine

– iodine

Section 5.2

• Substances are either organic or inorganic.

• Compounds that contain carbon, with a few exceptions, are classified as organic compounds.

Formulas and Names of Covalent Compounds

Section 5.2

• Compounds that do not contain carbon are called inorganic compounds.

• If inorganic compounds contain only two nonmetal elements, they are bonded covalently and are referred to as molecular binary compounds.

Formulas and Names of Covalent Compounds (cont.)

Section 5.2

• Naming the compound

– Name of the first nonmental farthest left on the periodic table is listed first, followed by name of second nonmetal with its ending changed to –ide.

– Add a prefix to the name of each element to indicate how many atoms of each element are present.

Formulas and Names of Covalent Compounds (cont.)

Section 5.2

Formulas and Names of Covalent Compounds (cont.)

Section 5.2

Formulas and Names of Covalent Compounds (cont.)