Binary compound composed of two elements
Naming binary ionic compounds (type I )
1- The cation always named 1st and the anion 2nd.
2- Monoatomic cation talks the name of the element
3- Monoatomic anion takes root of the name of element plus -ide .
Examples:
Naming binary ionic compounds (type II)
Type I: metal form single type of cations such as Na+
Type II: metal form many type of cations such Fe2+, F3+
In type II, the charge on the metal cation must be specified
Systematic names for these ions obtained by adding roman numerals in bracts to indicate the charge on cation such as Fe2+→ Iron(II) and ion such Fe3+ → Iron(III) ion.
In older system: The ion with higher charge has a name ending in (-ic) and the one with the lower charge has a name ending in (-ous) such Fe3+ → ferric ion and Fe2+ → ferrous ion .
Note that mercury(I) ion always occur bound together to form Hg22+ ions.
**Although these are transition metals, they form only one type of ion and a roman numeral is not used.
Rules for predicting the charges on
monatomic ions
1-
Most of the main-group metallic elements have one monatomic cation with a
charge equal to the group number in the periodic table. Such as Al3+ (Group IIIA).
2-
Some metallic elements (main-group) of high atomic number are exceptions to the
previous rule; they have more than one cation. Such as Pb2+
and
Pb4+ (Group
IV A)
3-
Most transition elements form more than one monatomic cation; each with a
different charge. Most of these elements have one ion with a charge of +2
(exceptions: Ag+,
Cd2+ and
Zn2+).
Example: Iron
has common cations Fe2+ and
Fe3+.
Copper has common cations Cu+ and Cu2+.
4-
The charge on a monatomic anion for a nonmetallic main-group element equals the
group number minus 8. Such as Oxygen has the monatomic anion O2_. (Group VIA).
Ionic compounds with polyatomic ions
For
example ammonium nitrate NH4NO3
have NH4+ and
NO3_,
HENCE MUST BE MEMORIZED.
Naming binary covalent compounds(type
III)
Formed
between two non-metals.
1-
The first element in the formula named first using the full element name.
2-
The second named like anion
3-
Prefixes used to denote number of atoms
4-
Prefix (mono-) never used for the 1st element
Example: CO
carbon monoxide not monocarbon
monoxide
Order of Elements in the Formula:
By
this convention, the nonmetal or metalloid occurring first in
the following sequence is written first in the formula of the compound.
Element:
B → Si → C → Sb → As → P → N → H → Te → Se → S → I → Br → Cl → O → F
To
see how these rules apply, we will now consider the names of the several
covalent compounds formed by nitrogen and oxygen:
Note:
Often
o or a
dropped from prefix when element begin with vowel.
Some
compound has common names such as water (H2O),
ammonia (NH3),
hydrogen peroxide (H2O2)
Acids:
When
dissolved in water, certain molecules produce a solution containing free H+ ions (protons). Here we will simply present the
rules for naming acids. An acid is a molecule in which one or more H+ ions are attached to an anion.
The
rules
for naming acids depend on whether the anion contains oxygen:
vIf the name of the anion
ends in -ide, the
acid is named with the prefix hydro-
and
the suffix -ic. For example, when gaseous HCl is
dissolved in water, it forms hydrochloric acid.
When
the anion contains oxygen
vIf anion name ends with -ate then
suffix -ic acid is added to the root name.
vIf anion name ends with-ite
then suffix -ous acid is added to the root name.