naming ions monatomic ions ions consisting of a single atom with a + or - charge anions (-) most...
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Naming IonsNaming Ions
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 halogen compoundsNaming 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-).
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.
Naming Ions
Transition Metals*Charges must be determined by the number of electrons lost*Can have varying charges for the same elements
*Naming: Two MethodsStock System: Roman numerals in parenthesesExample: Fe2+
Written: Iron(II) ion
Read: “Iron two ion,”
Example: Fe3+
Written: Iron(III) ion
Read: “iron three ion”
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
Naming IonsTransition 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+
Naming IonsPolyatomic 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
Naming Ions
Polyatomic Ions
When a polyatomic ion contain Hydrogen, it is like adding a H+ with another polyatomic ion
Examples: H+ + CO32- ----> HCO3
-
Carbonate Hydrogen Carbonate
H+ + PO43- ----> HPO4
2-
Phosphate Hydrogen Phosphate
Ionic BondsIonic Bonds
Bonds between ions
Based on “opposites attract”
Cation + Anion (+) charge (-) charge
(metals) (nonmetals)
NamingNaming
Chemical name + Chemical name of cation of anion PLUS
“ide” ending
Example: Na+ + Cl-
NaCl Sodium chloride (capitalized) (not capitalized)
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
Chemical Name Sodium chloride
Swap charges Na1+ + Cl1- superscript =
charge on ion
Na1 + Cl1 subscript =
number of atoms
needed to form the compound
Chemical Formula NaCl
Naming and Writing FormulasBinary 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
Naming and Writing FormulasBinary Ionic Compounds
Naming and Writing FormulasCompounds 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
Naming and Writing Formulas
Compounds with Polyatomic Ions
Naming and Writing FormulasNaming 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
Naming and Writing FormulasGuidelines for Naming
1) Confirm the compound is a molecular compound (2 nonmetals)
2) Omit mono- when the the formula contains only one of the first element in the name
3) 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
Naming and Writing Formulas
Practice
Write the name of these molecular compounds:
a) NCl3
b) BCl3
c) NI3
d) SO3
e) N2H4
f) N2O3
Naming and Writing Formulas
Practice
Write the formulas for these binary molecular compounds:
a) Phosphorus pentachloride
b) Iodine heptafluoride
c) Chlorine trifluoride
d) Iodine dioxide
e) Carbon tetrabromide
f) Diphosphorus trioxide
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
Naming and Writing Formulas
Naming Acids
1) 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-
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-
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-
Naming and Writing FormulasWriting 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.
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
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 43.13 g of Mg and 56.87 g of S
Ratio: 0.758/1
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
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: 2.41 g of C/3.22 g of O = 0.748 g C/g O
B: 6.71 g of C/17.9 g of O = 0.375 g C/ g O
0.748 g/0.375 g = 1.99/1 = about 2:1
The Laws Governing Formulas and Names
The Laws of Multiple Proportions
Naming Chemical Compounds
The Laws Governing Formulas and Names
Naming Chemical Compounds
Guidelines:
1) -ide generally indicates a binary compound
2) -ite or -ate means a polyatomic ion that includes O
3) Prefixes generally indicate a molecular compound
4) A Roman numeral shows the charge of the cation