Writing and Naming Ionic Formulas
Ionic bond (Compound)
A chemical bond in which a metal atom loses an electron to form a positive cation and a nonmetal atom gains an electron to form a negative ion
Coefficient
A whole number that appears in front of the formula and chemical equation indicates the number of moles
Aluminum bromide
AlBr₃
Formula for Aluminum fluoride
AlF₃
Aluminum nitride
AlN
Aluminum sulfide
Al₂S₃
Write the chemical formula for aluminum sulfide
Al₂S₃
Ion
Atom with a charge
Barium fluoride
BaF₂
Barium oxide
BaO
Calcium nitrate
Ca(NO₃)₂
Calcium bromide
CaBr₂
Calcium chloride
CaCl₂
Calcium oxide
CaO
Write the chemical formula for Calcium sulfide
CaS
Write the chemical formula for calcium nitride
Ca₃N₂
copper (II) nitride
Cu3N2
Potassium iodide
KI
Formula for potassium hydroxide
KOH
Formula for potassium oxide
K₂O
Potassium sulfide
K₂S
Write the chemical formula for potassium nitride
K₃N
lithium bromide
LiBr
Formula for lithium fluoride
LiF
Lithium nitrate
LiNO₃
Write the chemical formula for lithium sulfide
Li₂S
Cross cross method
Make the formula by criss-crossing the charges of each atom.
magnesium chloride
MgCl2
Magnesium chloride
MgCl₂
Formula for magnesium fluoride
MgF₂
Magnesium sulfide
MgS
Write the chemical formula for manganese(IV) sulfide
MnS₂
Naming ionic compounds w/ transition metals
Must use Roman numerals after metal/cation to indicate which charge
Formula for nitrogen dioxide
NO₂
Sodium fluoride
NaF
Sodium iodide
NaI
Sodium sulfide
Na₂S
Sodium nitride
Na₃N
Anion
Negatively charged ion results from gain of electrons nonmetals only
Write the chemical formula for phosphorous trichloride
PCl₃
Formula for phosphorus pentafluoride
PF₅
Cation
Positively positively charged ion. results from loss of electrons. Metals only
Subscript
Small numbers to the lower right of the symbol they represent the number of Adams of the element in the compound
Naming binary ionic compounds
Write the name of positive ion first. Write name of negative ion last, followed by "ide".
Al2Se3
aluminum selenide
when writing the formula for any ionic compound, the charge of the ions must
balance
roman numerals indicate the oxidation number of
cations having multiple possible states
binary ionic compounds are
composed of 2 elements one positive and one negative charge
Crisscross Method
finding the chemical formula of a metal and a nonmetal that combine in an ionic bond
PbS
lead II sulfide
MgCl2
magnesium chloride
to show more than one polyatomic ion in a chemical formula you should
place parentheses around the polyatomic ion & use subscript
How do you write the formula for a compound containing a polyatomic charge?
symbol or formula for cation followed by symbol for anion and use subscript to balance charge
in writing formulas for ionic compounds write
the cation is listed first followed by the anion