Naming Monatomic and Polyatomic Ions

Naming Monatomic ion:

A monatomic ion is a charged particle consisting of a single atom. (e.g Na+, F-, S²-)

a) Naming monatomic metal ions:

Add the word "ion" after the name of the metal.

Examples:

"Na" Sodium metal → Sodium ion ( Na+ ) + 1 electron

the name of monatomic metal ion is Sodium ion

"Ca" Calcium metal → Calcium ion ( Ca²+) + 2 electrons​

the name of monatomic metal ion is Calcium ion

If the metal ion has more than one possible charge...

1. Add the Roman numeral of the charge in bracket after the name of the metal.

2. Then add the word "ion" .

— [ element name +(charge in Roman numeral) + "ion" ]

Examples:

"Ti3+" Titanium metal →Titanium(III)ion + 3 electrons

name of this monatomic metal ion is Titanium(III)ion

"Co2+" Cobalt metal Cobalt(II)ion + 2 electrons

name of this monatomic metal ion is Cobalt(II)ion

Exercise: write the formula of the ions.

​​a.) Iron(II)ion → ​Fe²+ b.) Chromium(III)ion → Cr³+


b) Naming monatomic non-metal ions:

Change the original ending of the non-metal's name to "ide". (element stem name + "ide")

Examples:

"O" Oxygen → Oxygen → Ox Oxide (O2- )

"S" Sulphur → Sulphur → Sulph → Sulphide (S2-)

Naming Polyatomic ions:

A Polyatomic ion is a charged particle of two or more atoms. (e.g OH- , NH4+ ​)

We don't need to know how to name the Polyatomic ions, we should know those Polyatomic ions.

Here are some common examples:

​a. NH4+ ammonium ion, (The only positive polyatomic ion we need to know)


b. “ate” ions: contain an atom bonded to several oxygen atoms:

NO3- : Nitrate PO4³- :Phosphate SO4²- : Sulfate

CO3²- : Carbonate CH3CO²- : Acetate ClO³- : Chlorate

c. “ite” ions: remove one oxygen from the “ate” ion and keep the same charge:

NO2- : Nitrite PO3³- : Phosphite SO3²- : Sulfite

ClO2- : Chlorite

d. other common complex ions:

OH- : Hydroxide CN- : Cyanide ​


Links:
http://antoine.frostburg.edu/chem/senese/101/compounds/polyatomic.shtml#namingpractices

http://antoine.frostburg.edu/chem/senese/101/compounds/polyatomic.shtml#namingpractices


http://www.fordhamprep.org/gcurran/sho/sho/lessons/lesson53.htm