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 .
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:
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)
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.