Molecular compounds The difference between molecules and the ionic compounds we’ve been studying so far…..

Molecules are compounds formed from one or more non- metals

These atoms share electrons (this is called covalent bonding); they don’t gain or lose electrons

Molecules are compounds formed from one or more non-metals These atoms share electrons (this is called covalent bonding); they don’t gain or lose electrons The atoms that form molecules are from the group of atoms which normally gain electrons (anions

Oxygen atom has how many electrons? Ion? Hydrogen atom has how many electrons? Ion?

Hydrogen Oxygen H 2 O is a molecular compound The atoms share electrons and stick together There is no charge to the molecule, unlike ions

Magnesium chloride is an ionic compound MgCl 2 Cl 17 P Mg 12 P Cl 17 P +2

Naming binary molecular compounds Use prefixes to write the names for binary molecular compounds to indicate the number of each element The order of elements in a binary molecular compound is increasing group number o CO 2, not O 2 C CO 2, what we exhale, is carbon di oxide CCl 4, dry cleaning fluid, is carbon tetra chloride They all end in –ide, like binary ionic compounds

Prefixes used in naming binary molecular compounds PrefixNumberPrefixNumber mono-1hexa-6 di-2hepta-7 tri-3octa-8 tetra-4nona-9 penta-5deca-10

Acids Acids are any compounds which, when dissolved in water, produce hydrogen ions (H + ) They are any ionic compounds where the cation is H + We name them using “hydro” followed by the anion name ending in -ic

Examples of acids Binary acids – HFhydrofluoric acid – HClhydrochloric acid Polyatomic acids – HNO 3 nitric acid – HNO 2 nitrous acid