1. Chemical Names
and Formulas

2. Ions consisting of a single atom with a + or - charge
Monatomic Ions
Ions consisting of a single atom with a + or - charge
Anions (-)
Most from 5A, 6A, 7A
Naming: Start with the stem of the element’s name ending with -ide
Example: Fluoride, Chloride, Nitride
Cations (+)
Most from Groups 1A, 2A, 3A
Naming: Same as the name of the metal, followed by ion or cation
Example: Sodium Ion, Potassium Ion
Naming Ions

3. Naming halogen compounds
When combined with other elements in simple compounds the name of the halogen element changes slightly from ...ine to ...ide.
Fluorine forms a fluoride (ion F-), chlorine forms a chloride (ion Cl-), bromine a bromide (ion Br-) and iodine an iodide (ion I-).
Naming halogen compounds

4. The other element at the start of the compound name e. g
The other element at the start of the compound name e.g. hydrogen, sodium, potassium, magnesium, calcium, etc. remains unchanged.
So typical halogen compound names are,  potassium fluoride, hydrogen chloride, sodium chloride, calcium bromide, magnesium iodide etc.
The elements all exist as X2 or X-X, diatomic molecules where X represents the halogen atom.

6. Naming Ions
Transition Metals *Charges must be determined by the number of electrons lost *Can have varying charges for the same elements *Naming: Two Methods Stock System: Roman numerals in parentheses
Example: Fe2+
Written: Iron(II) ion
Read: “Iron two ion,”
Example: Fe3+
Written: Iron(III) ion
Read: “iron three ion”

7. Naming Ions Transition Metals
Classical System: suffix used with root name to name the ion
Example: Fe2+
Written: Ferrous Ion
Example: Fe3+
Written: Ferric Ion
Example: Cr2+
Written: Chromous Ion
Example: Cr3+
Written: Chromic Ion

8. Naming Ions Transition Metals
-Classical System: some names may seem unfamiliar
-Iron: Ferr-
-Copper: Cupr-
-Tin: Stann-
-Lead: Plumb-
-Some transition metals have only one charge
Ag+
Cd2+
Zn2+

9. Naming Ions Polyatomic Ions Ions composed of more than one atom
Tightly bound groups of atoms that behave as one unit and have a charge
All Anions ending in -ite or -ate contain Oxygen
“-ites” have one less oxygen than “-ates”
Examples: ClO2- Chlorite
ClO3- Chlorate
Cr2O72- Dichromate
PO33- Phosphite

10. Naming Ions Polyatomic Ions
When a polyatomic ion contain Hydrogen, it is like adding a H+ with another polyatomic ion
Examples: H+ + CO > HCO3-
Carbonate Hydrogen Carbonate
H+ + PO > HPO42-
Phosphate Hydrogen Phosphate

11. Based on “opposites attract”
Ionic Bonds
Bonds between ions
Based on “opposites attract”
Cation + Anion
(+) charge (-) charge
(metals) (nonmetals)

12. Naming Chemical name + Chemical name of cation of anion PLUS
“ide” ending
Example: Na Cl-
NaCl
Sodium chloride
(capitalized) (not capitalized)

13. Unlike atoms, compounds are stable when they are neutral
There is no way to know from the name how many atoms of each kind are present in an ionic compound
Therefore, the chemical formula is needed to determine the number of each atom necessary for a reaction to occur

14. Chemical Name Sodium chloride
Swap charges Na Cl1- superscript = charge on ion
Na Cl1 subscript = number of atoms needed to form the compound
Chemical Formula NaCl

15. Naming and Writing Formulas
Binary Ionic Compounds
An ionic or molecular compound composed of two elements
Antoine-Laurent Lavoisier developed a naming system w/ other chemists
Naming: Place the cation first followed by the anion.
Formula: Cation first, Anion second
Remember, total charge equals zero!
Example: Cs2O = Cesium Oxide (Ionic)
CuO = Copper(II) Oxide (Ionic) Hint: 1:1 ratio

17. Naming and Writing Formulas
Binary Ionic Compounds

18. Naming and Writing Formulas
Compounds with Polyatomic Ions
Recall that a Polyatomic Ion acts as one unit
Naming: Place the cation first followed by the anion.
Formula: Cation first, Anion second
Example: PbSO4 = Lead(II) Sulfate
K2HPO4 = Potassium Hydrogen Phosphate

19. Naming and Writing Formulas
Compounds with Polyatomic Ions

20. Naming and Writing Formulas
Naming Binary Molecular Compounds
The prefix tells how many atoms of each element are present in each molecule of the compound
Carbon Monoxide vs. Carbon Dioxide
Mono- indicates one oxygen
Di- indicates two oxygens

21. Naming and Writing Formulas
Guidelines for Naming
Confirm the compound is a molecular compound (2 nonmetals)
Omit mono- when the the formula contains only one of the first element in the name
Add -ide to the second element in the formula
Guidelines for Formula Writing
1) Use the prefixes in the name to tell you the subscripts in the formula

22. Naming and Writing Formulas
Practice
Write the name of these molecular compounds:
NCl3
BCl3
NI3
SO3
N2H4
N2O3

23. Naming and Writing Formulas
Practice
Write the formulas for these binary molecular compounds:
Phosphorus pentachloride
Iodine heptafluoride
Chlorine trifluoride
Iodine dioxide
Carbon tetrabromide
Diphosphorus trioxide

24. Naming and Writing Formulas
Acids
A compound that contains one or more hydrogen atoms and produces hydrogen ions (H+) when dissolved in water
Acids consist of an anion and as many H+ as are necessary to make the atom electrically neutral. HnX

25. Naming and Writing Formulas
Naming Acids
When the anion’s name ends in -ide, the acid’s name begins with hydro- and the stem of the anion’s name ends in -ic, followed by the word acid.
Example: Hydrochloric Acid HCl
Anion: Chloride Cl-

26. Naming and Writing Formulas
Naming Acids
2) When the anion’s name ends in -ite, the acid’s name is the stem of the anion with the suffix -ous, followed by the word acid.
Example: Sulfurous Acid H2SO3
Anion: Sulfite SO32-

27. Naming and Writing Formulas
Naming Acids
3) When the anion’s name ends in -ate, the acid’s name is the stem of the anion with the suffix -ic, followed by the word acid.
Example: Nitric Acid HNO3
Anion: Nitrate NO3-

28. Naming and Writing Formulas
Writing Formulas for Acids
Use the rules for naming acids in reverse to write formulas for acids.
Find the anion in the acid. Then, match its charge with the appropriate number of H+ ions to make the formula electrically neutral.

29. Naming and Writing Formulas
Names and Formulas for Bases
An ionic compound that produces hydroxide ions (OH-) when dissolved in water.
These are named in the same way as other ionic compounds: cation first and anion second.
Common Bases
NaOH Sodium Hydroxide
Ba(OH)2 Barium Hydroxide
Ca(OH)2 Calcium Hydroxide

30. The Laws Governing Formulas and Names The Laws of Definite Proportions
In samples of any compound, the masses of the elements are always in the same proportions
Example:
100 g of MgS has g of Mg and g of S
Ratio: 0.758/1

31. The Laws Governing Formulas and Names
The Laws of Multiple Proportions
Whenever the same two elements form more than one compound, the different masses of one element that combine with the same mass of the other element are in the ratio of small whole numbers
Example: 16 g of O in H2O2 to every 1 g of H = 2:1
8 g of O in H2O to every 1 g of H

32. The Laws Governing Formulas and Names
The Laws of Multiple Proportions
Carbon and Oxygen can form two compounds.
A: contains 2.41 g of C for every 3.22 g of O
B: contains 6.71 g of C for every 17.9 g of O
A: g of C/3.22 g of O = g C/g O
B: g of C/17.9 g of O = g C/ g O
0.748 g/0.375 g = 1.99/1 = about 2:1

33. The Laws Governing Formulas and Names
The Laws of Multiple Proportions

34. Naming Chemical Compounds

35. The Laws Governing Formulas and Names
Naming Chemical Compounds
Guidelines:
-ide generally indicates a binary compound
-ite or -ate means a polyatomic ion that includes O
Prefixes generally indicate a molecular compound
A Roman numeral shows the charge of the cation