22.3 Notes Continued

22.3 Notes Continued

Part C

Objectives

Write formulas and names for covalent compounds

Covalent compounds

Made of just nonmetals Share electrons Smallest piece is a molecule Can’t be held together because of

opposite charges Can’t use charges to figure out how

many of each atom

Covalent/Molecular compounds

Ionic compounds use charges to determine how many of each element.

Molecular compounds name tells you the number of atoms.

Uses prefixes to tell you the number

Naming Covalent Compounds

Prefix element name Prefix element name-ide The last vowel of the prefix is dropped when the

second element begins with a vowel as in pentoxide• No double vowels when writing names (oa oo)• Often the prefix mono- is omitted from the first element

when naming• Many times it is also omitted from 2nd element, though

it is used for emphasis in some cases

Examples

Carbon dioxide – CO2

Dihydrogen monoxide – H2O Dinitrogren pentasulfide – N2S5

Tricarbon tetrafluoride – C3F4

Name These

N2O NO2 Cl4O7 NBr3 BaCl5

Writing formulas for Covalent Compounds

Simply write the chemical symbol Subscript is derived from the

prefix Mono = 1, di = 2, tri = 3, ect

Write formulas for these

diphosphorus pentoxide tetraiodide nonoxide sulfur hexaflouride Carbon tetrahydride phosphorus trifluoride

Hydrates

• An ionic compound that has water chemically attached to its ions and written into its chemical formula

Hydrates pg. 708

• These same prefixes are used when naming the hydrates previously discussed.

• The main ionic compound is named the regular way, but the number of water molecules in the hydrate is indicated by the Greek prefix.

Chemical formula • # H2O

Hydrates

BeBr * 3 H2O

Calcium nitride hexahydrate

In-Class Assignment/Homework

Finish naming Molecular Compounds WKT

Naming practice on the board