1. Naming Compounds Writing Formulas

2. Systematic Naming
There are too many compounds to remember the names of them all.
Compound - made of two or more elements.
Name should tell us how many and what type of atoms.

3. Atoms and ions Atoms are electrically neutral.
Same number of protons and electrons.
Ions are atoms, or groups of atoms, with a charge.
Different numbers of protons and electrons.
Only electrons can move.
Gain or lose electrons.

4. F-1 O-2 Anion A negative ion. Has gained electrons.
Nonmetals gain electrons.
Charge is written as a superscript on the right.
F-1
Has gained one electron
O-2
Has gained two electrons

5. K+1 Ca+2 Cations Positive ions. Formed by losing electrons.
More protons than electrons.
Metals form cations.
K+1
Has lost one electron
Ca+2
Has lost two electrons

6. Compounds Follow the Law of Definite Proportion.
Have a constant composition.
the same number/type of atoms every time.

7. Two Types of Compounds . Molecular compounds Made of molecules.
Made by joining nonmetal atoms together into molecules.
Covalent bonds

8. Two Types of Compounds . Ionic Compounds Made of cations and anions.
Metals and nonmetals.
The cation and anions surround each other in a crystal.
Smallest piece is a FORMULA UNIT.

9. Two Types of Compounds Ionic Molecular Smallest piece Formula Unit
Molecule
Types of elements
Metal and Nonmetal
Nonmetals
Solid, liquid or gas
State
solid
Melting Point
High >300ºC
Low <300ºC

10. Chemical Formulas
Shows the kind and number of atoms in the smallest piece of a substance.
Molecular formula- number and kinds of atoms in a molecule.
CO2
C6H12O6

11. Formula Unit
The smallest whole number ratio of atoms in an ionic compound.
Ions surround each other so you can’t say which is hooked to which.

12. Charges on ions
For main group elements, the Periodic Table is used to predict charges.
Including the charge when they are ions.

13. +1 +2 +3 -3 -2 -1

14. Naming Cations
Cation- if the charge is always the same, just write the name of the metal.
Transition metals can have more than one type of charge.
Indicate the charge with Roman numerals in parenthesis.
Ex. Iron(II) = Fe+2

15. Naming Anions Anions are negative ions.
Elements change the ending to –ide
F-1 fluorine → fluoride
Oxygen → oxide

16. Polyatomic ions Ammonium – NH4+1
Groups of atoms that stay together and have a charge. Memorize the most common ones.
Acetate C2H3O2-1
Nitrate NO3-1
Nitrite NO2-1
Hydroxide OH-1
Ammonium – NH4+1

17. Naming Binary Ionic Compounds
Binary Compounds - 2 elements.
a cation and an anion.
To write the names just name the two ions.(positive is ALWAYS first)
NaCl = Na+ Cl- = sodium chloride
MgBr2 = Mg+2 Br- = magnesium bromide

18. Naming Binary Ionic Compounds
Only problem -- transition metals.
Must figure out the positive charge.
The compound is neutral.
same total + and – charges.
Use the anion to determine the charge on the positive ion.

19. examples name CuO Need the charge of Cu O is -2
copper must be +2 = copper (II) oxide
Name CoCl3
Cl is -1 and there are three of them = -3
Co must be +3 = cobalt (III) chloride

20. Naming Binary Ionic Compounds
Write the name of Cu2S.
S is -2, the Cu2 must be +2, so each one is = copper (I) sulfide
Fe2O3
Each O is x -2 = -6
2 Fe must = +6, so each is +3
iron (III) oxide

21. Ternary Ionic Compounds
Will have polyatomic ions
At least three elements
Just name the ions
NaNO3 sodium nitrate
CaSO4 calcium sulfate
CuSO3 copper (II) sulfite
(NH4)2O ammonium oxide

22. Writing Formulas Cation is first, then anion.
The charges have to add up to zero.
(Total positive = total negative)
Balance the charges by adding subscripts after the symbol.
Put polyatomic ions in parenthesis.
Charges are not included in the formula.

23. Things to look for
If cations have ( ), the Roman numeral is the charge.
If anions end in -ide they are probably right off the periodic table (Monoatomic)
If anion ends in -ate or -ite it is polyatomic

24. Molecular compounds and formulas
made of nonmetal + nonmetal
smallest piece is a molecule
can’t use charges to figure out how many of each atom (covalent)
Use numerical prefixes

25. Prefixes 1 mono- 6 hex- 2 di- 7 hept- 3 tri- 8 oct- 4 tetra- 9 non-
5 pent dec-
To write the name write:
prefix+element prefix+element –ide.

26. One exception: Don’t write mono- for one atom of the first element.
Name these compounds
N2O
NO2
Cl2O7
CBr4
CO2
BaCl2

27. Write formulas for these
diphosphorus pentoxide
tetraiodine nonoxide
sulfur hexafluoride
nitrogen trioxide

28. Writing names and Formulas
Acids
Writing names and Formulas

29. Acids Compounds that give off hydrogen ions when dissolved in water.
Must have H in them.
will always be some H next to an anion.
The anion determines the name.

30. Naming acids
If the anion attached to hydrogen is ends in -ide, put the prefix hydro- and change -ide to -ic acid
HCl - hydrogen ion and chloride ion
hydrochloric acid
H2S hydrogen ion and sulfide ion
hydrosulfuric acid

31. Naming Acids If the anion has oxygen in it it ends in -ate or -ite
change the suffix -ate to -ic acid
HNO3 Hydrogen and nitrate ions
Nitric acid
change the suffix -ite to -ous acid
HNO2 Hydrogen and nitrite ions
Nitrous acid

32. Name these HF
H3P
H2SO4
H2SO3
HCN
H2CrO4

33. Writing Formulas Hydrogen will always be first. name tells the anion
Must be neutral.
Starts with hydro- no oxygen, -ide
no hydro, -ate comes from -ic, -ite comes from -ous

34. Write formulas for these
hydroiodic acid
acetic acid
carbonic acid
phosphorous acid
hydrobromic acid