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1. Naming TWO NON-METALS
Binary Compounds of Two Nonmetals
Given Formula, Write the Name
The Greek System
A binary compound is one made of two different elements. There can be one of each element
such as in CO or NO. There can also be several of each element such as BF or
OCl2.
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Attach the selected prefix to the name of the first element in the formula. If no prefix is to
be used, begin with the name of the first element.
Example: We indicate the N2 portion of N2O3 withdinitrogen.
Select a prefix to identify the subscript for the second element (even if its subscript is
understood to be one).Leave the "a" off the end of the prefixes that end in "a" and the o off of
mono- if they are placed in front of an element whose name begins with a vowel (oxygen oriodine).
Example: The name of N2O3 grows to dinitrogen tri-.
Write the root of the name of the second element in the formula as shown below.
Example: The name of N2O3 becomes dinitrogen triox-.
Add -ide to the end of the name.
Example: The name of N2O3 is dinitrogen trioxide.
Prefixes
1 - mon(o)
2 - di
3 - tri
4 - tetr(a)5 - pent(a)
6 - hex(a)7 - hept(a)
8 - oct(a)
9 - non(a)
10 - dec(a)
Roots of the Nonmetals
H - hyd
C - carb
N - nitr
P - phosphAs - arsen
O - oxS - sulf
Se - selen
F - fluor
Cl - chlorBr - brom
I - iod
Exceptions
Hydrogen atoms always form one covalent bond, and halogen atoms (group 17 or 7A) usually
form one bond. Thus hydrogen reacts with halogens to form compounds with the general
formula of HX, with the X representing the halogen. Because this is common knowledge amongscientists and science students, these compounds are often named without prefixes. For example,
HF can be named hydrogen fluoride or hydrogen monofluoride. Likewise, HCl can be named
hydrogen chloride or hydrogen monochloride, HBr can be named hydrogen bromide or hydrogenmonobromide, and HI can be named hydrogen iodide or hydrogen moniodide. For similar
reasons, H2S can be named hydrogen sulfide or dihydrogen monosulfide.
Converting Names to Formulas
The first step in writing formulas when given the systematic name of a binary covalent
compound is to recognize the name as representing a binary covalent compound. It will have one
of the following general forms.
prefix (name of nonmetal) prefix (root of name of nonmetal)ide (e.g. dinitrogen pentoxide)
or(name of nonmetal) prefix (root of name of nonmetal) ide(e.g. carbon dioxide)
or(name of nonmetal) (root of nonmetal) ide (e.g. hydrogen fluoride)Follow these steps for writing formulas for binary covalent compounds when you are given a
systematic name. Notice that they are the reverse of the steps for writing names from chemical
formulas.
Write the symbols for the elements in the order mentioned in the name.
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Write subscripts indicated by the prefixes. If the first part of the name has no prefix,
assume it is mono-.
Remember that HF, HCl, HBr, HI, and H2S are often named without prefixes. You will also beexpected to write formulas for the compounds whose nonsystematic names are listed above.
3. Naming HYDROXIDE AND A METAL
Naming Ionic Compounds
Key Concepts
Positively charged ions are called cations
Negatively charged ions are called anions
The cation is always named first.
Cations
Cations can be metals or polyatomic ions
The ammonium ion (NH4+) is an example of a polyatomic cation Hydrogen can also form a cation, H+, in which case the name hydrogen is used in naming.
For metals that have only one possible charge (valency) the name of the metal is used.Examples are Group I metals (charge 1+), Group II metals (charge 2+), Aluminium (charge 3+), Zinc
(charge 2+), Silver (charge 1+)
For metals that can have more than one charge (valency) the name of the metal is succeeded by
the valency in capital Roman numerals in brackets
OR
by using the suffix -ous for the lowest valency and -ic for the highest valency and sometimes with the
Latinised name for the metal
Anions
Anions can be a negatively charged element or a polyatomic ion
Negatively charged elements have the suffix -ide
Examples are oxide (O2-), sulfide (S2-), fluoride (F-), chloride (Cl-), bromide (Br-), iodide (I-), nitride
(N3-), hydride (H-)
Polyatomic ions which include oxygen in the anion have the suffixes -ate or -ite. "ate" means
there is more oxygen in the anion than one ending in "ite"
Element Cation Preferred Name Other Name
copperCu+ copper (I) cuprous
Cu2+ copper (II) cupric
iron Fe2+
iron (II) ferrousFe3+ iron (III) ferric
leadPb2+ lead (II) plumbous
Pb4+ lead (IV) plumbic
mercuryHg2
2+ mercury (I) mercurous
Hg2+ mercury (II) mercuric
tinSn2+ tin (II) stannous
Sn4+ tin (IV) stannic
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Examples: sulfate (SO42-) has more oxygen than sulfite (SO32-), nitrate (NO3-) has more oxygen in the
anion than nitrite (NO2-)
Other examples are carbonate (CO32-), phosphate (PO43-) and permanganate (MnO4-)
Exception: OH- is named hydroxide
ExamplesIonic Compounds containing ions of elements
MgOCATION: Mg2+ is named magnesium as magnesium belongs to Group (II) and can only have one charge
(valency)
ANION: O2- is named oxide
Name of compound is magnesium oxide
FeS
CATION: Fe2+ is named iron (II) or ferrous as iron can have a charge of either 2+ or 3+
ANION: S2- is named as sulfide
Name of compound is iron (II) sulfide or ferrous sulfide
LiH
CATION: Li+ is named as lithium since lithium is a Group I metal and can have only one charge
(valency)
ANION: H- is named as hydrideName of compund is lithium hydride
H2S
CATION: H+ is named as hydrogen
ANION: S2- is named as sulfideName of compound is hydrogen sulfide
Ionic compounds containing polyatomic ions
NaOH
CATION: Na+ is named as sodium (Group I metal)
ANION: OH- is named as hydroxide
Name of compound is sodium hydroxide
CaCO3
CATION: Ca2+ is named as calcium (Group II metal)ANION: CO32- is named as carbonate
Name of compound is calcium carbonate
FeSO4
CATION: Fe2+ named as iron (II) or ferrous
ANION: SO42- named as sulfate
Name of compound is iron (II) sulfate or ferrous sulfate
FeSO3
CATION: Fe2+ named as iron (II) or ferrous
ANION: SO32- named as sulfite
Name of compound is iron (II) sulfite or ferrous sulfite (NH4)3PO4
CATION: NH4+ named as ammoniumANION: PO43- named as phosphate
Name of compound is ammonium phosphate