1. Chemical Names and Formulas
Chapter 7
Chemical Names and Formulas

2. Molecules and Molecular Compounds
Molecule – the smallest electrically neutral unit of a substance that still has the properties of a substance.
Molecular Compounds – Compounds composed of molecules.

3. Ions
Ions – atoms or groups of atoms that have a positive or negative charge.
Ions form when an atom or group of atoms gains or loses an electron.
There are two different types of ions: anions and cations.

4. Cations
Cation – any atom or group of atoms that has a positive charge.
Ex Sodium is a cation because it has 11 protons and only 10 electrons.
 Sodium has a charge of 1+
Na = Na+
(the number 1 is usually omitted)

5. Anions Anions – atoms or groups of atoms with a negative charge
Ex Chloride is an anion because it has only 17 protons and 18 electrons.
Chloride has a charge of 1-
-- Cl = Cl-

6. More Examples! Cations Symbol Anions Symbol
Aluminum Al Chlorate ClO3-
Cobalt(II) Co Fluoride F-
Lead (IV) Pb Hydroxide OH-
Magnesium Mg Nitride N3-
Mercury (II) Hg Oxide O2-
Potassium K Peroxide O22-

7. Ionic Compounds Ionic compounds are composed of cations and anions
They are usually composed of a metal cation and a non-metal anion
Ex – Sodium Chloride
sodium cation & chloride anion

8. Chemical Compounds
Chemical Formula – shows the kinds & numbers of atoms in the smallest representative unit of the substance.

9. Diatomic Compounds They are non metallic elements
Remember them!!!!! ( all 7 )
Hydrogen H2
Fluorine F2
Oxygen O2
Nitrogen N2
Chlorine Cl2
Bromine Br2
Iodine I2

10. Molecular Formulas
Molecular Formulas show the kinds and numbers of atoms present in the molecule of a compound.
Ex Ammonia = NH3
H N H H
**This structural formula shows that Ammonia has 3 atoms of Hydrogen and 1 atom of Nitrogen

11. Formula Units
Formula Units represent the lowest whole number ratio of ions in a compound.
Ex Sodium Chloride
1 Na+ to each Cl-
The ratio of ions is 1:1
NaCl

12. More Examples and Forming Compounds….
Magnesium Chloride
Contains magnesium cations (Mg2+) and chloride anions (Cl-)
Ratio is 1:2
Mg 2+ Cl –
-- MgCl2

13. Aluminum Chloride
Contains aluminum cations (Al3+) and chloride anions (Cl-)
Ratio is 1:3
Al Cl -
-- AlCl3

14. Type I Binary Ionic Group “A” metal – non metal
Name of metal + name of non metal +ide Ex
NaCl – Sodium Chloride
CaBr2 – Calcium Bromide
Al2O3 – Aluminum Oxide

15. Transition Metal – non metal
Name of metal + Roman Numeral + Non Metal + ide
Exceptions ( Ag+, Zn2+, Cd2+) Ex
Cu2O – Copper(I) Oxide
HgI2 – Mercury (II) Iodide

16. Type II Ternary Ionic Group “A” Metal-Radical
name of metal + name of radical
Transition Metal-Radical
name of metal+ Roman Numeral+ name of radical

17. Non Metal – Non Metal
Use Prefixes
Mono - Hexa
Di - Hepta
Tri - Octa
Tetra - Nona
Penta - Deca
Ex PCl 3 - Phosphorous Tri Chloride
SF Sulfur Hexa Flouride

18. Acids where X = mono-atomic or poly-atomic ions
Give off H+ ions when dissolved in H2O
Acids in form of HX
where X = mono-atomic or poly-atomic ions

19. 3 Rules
1) If X ends in - ide , acid name begins with the prefix hydro, and the stem of the anion has the suffix - ic followed by the word acid.
Ex: HCl X = Chloride
Hydrochloric Acid

20. 2) If X ends in -ite , the acid name is the stem of the anion with the suffix ous , followed by the word acid.
Ex: H2SO X= Sulfite
Sulfurous Acid

21. 3) If X ends in - ate, the acid name is the stem of the anion with the suffix - ic, followed by the word acid.
Ex: HNO3 X= Nitrate
Nitric Acid

22. Examples HClO3 - Chloric Acid HCN - Hydrocyanic Acid
H3PO4 - Phosphoric Acid
HF - Hydroflouric Acid
HC2H3O2 -Acetic Acid

23. More Examples H2SO4 - Sulfuric Acid HNO2 - Nitrous Acid
Hydroiodic Acid - HI
Chromic Acid - H2CrO4
Chlorous Acid - HClO2