1

Naming Compounds

Molecules and Molecular Compounds (Covalent Compounds)

•Two or more atoms tightly bound together •Bond by a covalent bond – the sharing of electrons

•Usually nonmetals bonded to other nonmetals

•Elements found in nature in molecular form – N2, O2, F2, Cl2, Br2, I2, H2

• Aka diatomic elements

2

•Molecular formulas – indicate actual numbers of and types of atoms in a molecule

•Term “molecule” refers only to covalently bonded substances.

•Empirical formulas – smallest possible whole number subscripts

•Use the Greek prefixes to name binary covalent compounds

3

Prefixes Used in Naming Molecular Compounds

Number Prefix

1 mono-

2 di-

3 tri-

4 tetra-

5 penta-

6 hexa-

7 hepta-

8 octa- ExampleGive the chemical formula for the following: silicon tetrachloride

disulfur dichloride

4

Ions and Ionic Compounds(Formula Units)

•Ion – formed when electrons are added or removed from an atom

•Cation – ion with a positive charge – typically metals

•Anion – ion with a negative charge – typically non-metals

•Ionic Compounds are always a metal bonded to a metal

•Compounds formed when cations and anions are attracted to each other

•Formed by the transfer of electrons 5

•Use the periodic table to predict charges (Drag out Periodic Table)

6

• atoms joined as a molecule but have a net positive or negative charge

7

Polyatomic ions –

Naming Ionic Compounds

•Cations – (the metals) – have the same name as the metal

•Must use roman numerals if dealing with a metal that can have more than one charge – i.e. the transition metals

•One-atom anions – (the nonmetals) – • Their ending changes to –ide

e.g. NaCl is sodium chloride

8

ExampleGive the chemical formula for the following:

magnesium sulfate

silver sulfide

lead(II)nitrate

9

Naming acids

I –ate it and it was –ic

I caught –ite –ous

Binary AcidsHydro ……. -ic

 

ExampleGive the formulas for the following:

1. hydrobromic acid

2. carbonic acid

3. Sulfurous acid

10

 

Cu + O2 → CuO 

  Mg + O2 → MgO    CuCO3 → CuO + CO2  

  Zn + HCl → ZnCl2 + H2     

11

  Zn + CuSO4 → ZnSO4 + Cu

      Zn(C2H3O2)2 + Na3PO4 → NaC2H3O2 + Zn3(PO4)2

      Na2SO3 + HCl → NaCl + H2O + SO2

12