ions and their compounds. remember how we can predict ion charges from the periodic table
TRANSCRIPT
IONIC COMPOUNDS
NaCl
MgCl2
Li3N
AlCl3
K2O
Metal + NonMetal Cations and Anions
both present Overall charge of
compound = 0 Number of electrons
given = number of electrons taken
Examples Pattern:
OVERALL CHARGE MUST = 0
Na+1 + Cl-1 = NaCl
Mg+2 + 2Cl-1 = MgCl2
3Li+1 + N-3 = Li3N
Al+3 + 3Cl-1 = AlCl3
2K+1 + O-2 = K2O
GIVE THE FORMULAS FOR THE COMPOUNDS THAT CONTAIN THE FOLLOWING PAIRS OF IONS
Ca2+ and S2-
Sr2+ and F-
Fe3+ and Cl-
Na+ and S2-
Mg2+ and O2-
CaS
SrF2
FeCl3
Na2S
MgO
NAMING TYPE I IONIC COMPOUNDS
Type I ionic compounds = the metal present forms only one type of cation
Metals in Groups 1, 2, 16 and 18, along with Al (3+), Zn (1+) and Ag (1+).
NAMING TYPE I BINARY IONIC COMPOUNDS
The cation is always name first and the anion second
A simple cation (from a single atom) takes its name from the name of the element. E.g. Na+ is called “sodium” in the names of the compounds containing this element.
A simple anion is named by taking the first part of the element name and adding –ide. E.g. Cl- ion is called “chloride”
Write the name for the compound by combining the names of the ions
“Sodium Chloride”
NAME THESE COMPOUNDS NaI
CaO
CaS
MgO
AlCl3
MgI2
Sodium Iodide
Calcium Oxide
Calcium Sulfide
Magnesium Oxide
Aluminum Chloride
Magnesium Iodide
TRANSITION METALS COMPLICATE THINGS
Many transition metals can form more than one cation. These cations have different charges
E.g. Au can form Au+ and Au3+, Fe can form Fe2+
and Fe3+
To indicate these different charges in the names of compounds, chemists use a system of Roman numerals conveying the different “oxidation numbers” of the cations
E.g. AuCl3 is called “Gold (III) Chloride; AuCl is called “Gold (I) Chloride)
The Roman numeral indicates the charge of the cation, NOT the number of ions present!!!!!!!
NAMING TYPE II BINARY IONIC COMPOUNDS
Type II compounds – the metal present can form 2 or more cations that have different charges (this will usually be a transition metal)
Give name of cation, the roman numeral indicating the cations charge, and the name of the anion (the root of the element forming the ion + -ide)
E.g. Fe2O3 = Iron (III) Oxide; FeO = Iron (I) Oxide
NAME THESE COMPOUNDS
HgO
PbCl4
HgCl2
SnBr4
CoCl3
Mercury (II) Oxide
Lead (IV) Chloride
Mercury (II) Chloride
Tin (IV) Bromide
Cobalt (III) Chloride