1. Naming of Chemical Compounds
Nomenclature
Naming of Chemical Compounds

2. Ionic Compounds
All ionic compounds are named by the simple rule: Name the cation name the anion Cations are positive ions, e.g., Na⁺ , Ba²⁺ Anions are negative ions, e.g., Cl⁻ , S²⁻

3. Ionic Compounds I
These ionic compounds all have cations that simply carry the name of the metal in the ion. Na⁺ is called a sodium ion Mg²⁺ is called a magnesium ion Such metals will be called type I metals.

4. Ionic Compounds I
All metals in column 1A and 2A are type I metals. Metals in 1A form ions with +1 charge. Li⁺ , K⁺ , etc. Metals in 2A form ions with +2 charge. Ca²⁺ , Sr²⁺ Also Ag⁺ (in 1B), Zn²⁺ (2B) , Al³⁺ (3A) will be counted as type I metals.

5. Ionic Compounds I
Type I anions are made from single atoms of elements. They are named by dropping the last few letters of the atomic name and adding ide. An ion of chlorine is called a chloride ion, Cl⁻ An ion of oxygen is called an oxide ion, O²⁻ An ion of phosphorus is called phosphide ion, P³⁻

6. Ionic Compounds I
Column 7A nonmetals form ions with charge -1 F⁻ , Cl⁻ , Br⁻ , I⁻ Column 6A nonmetals form ions with charge -2 O²⁻ , S²⁻ , Se²⁻ (selenide), Te²⁻ (telluride) Column 5A nonmetals form ions with charge -3 N³⁻ , P³⁻ , As³⁻ (arsenide)

7. Noble gases are called “noble” because they,
like nobility, have little interaction with the
other common elements.
They have stable electronic structures and do not need to bond with other atoms to reach stability.
Other elements gain and lose electrons to reach the noble gas electronic stability.

8. He Ne Ar Kr Xe 5A 6A 7A 8A 1A 2A 3A H⁻ Li⁺ Be²⁺ N³⁻ O²⁻ F⁻ Na⁺ Mg²⁺
Al³⁺
P³⁻
S²⁻
Cl⁻ Ar K⁺
Ca²⁺
As³⁻
Se²⁻
Br⁻ Kr
Rb⁺
Sr²⁺
Te²⁻ I⁻ Xe
Cs⁺
Ba²⁺

9. Names: Ionic Compounds I
NaCl has a sodium ion Na⁺ with a chloride ion Cl⁻
so it is called sodium chloride
by the simple rule:
name the cation name the anion
the word “ion” is not included

10. Names: Ionic Compounds I
Name the following:
CaF₂
calcium fluoride
BaS
barium sulfide
K₂O
potassium oxide
AlBr₃
aluminum bromide
Mg₃P₂
magnesium phosphide

11. Ionic Formulas I
Formulas need subscripts so all ionic charges in the compound add to zero. The subscript multiplies the ion it follows. Ions without subscripts are multiplied by 1, i.e., a subscript of 1 is not written. Ions are represented by atomic symbols. CaF₂ means 1 ion of calcium (Ca²⁺) for every 2 ions of fluoride (F⁻) so (+2)x1 + (-1)x2 = 0

12. Ionic Formulas I
To write a formula: for magnesium nitride write the atomic symbols Mg N write the charges cross the numbers without the charges Mg N 2 3 to get Mg₃N₂ so (+2)x3 + (-3)x2 = 0

13. Ionic Formulas I Write formulas for: aluminum fluoride
Al³⁺ with F⁻ so AlF₃
lithium phosphide
Li⁺ with P³⁻ so Li₃P
sodium iodide
Na⁺ with I⁻ so NaI
barium oxide
Ba²⁺ with O²⁻ so BaO
Ba₂O₂ reduces to lowest whole numbers BaO

14. Ionic Compounds II CuCl₂ and CuCl They cannot both be named
There are two different ionic compounds with copper and chloride ions:
CuCl₂ and CuCl
They cannot both be named
copper chloride
The chloride is the same in each compound
so the copper ions must be different.

15. Ionic Compounds II
In CuCl₂ one copper is combined with 2 Cl⁻ ions so it must be a Cu²⁺ ion. In CuCl one copper is combined with 1 Cl⁻ ion so it must be a Cu⁺ ion. So the two ions will be named differently.

16. Ionic Compounds II
In the old system the Cu²⁺ ion was named cupric ion and the Cu⁺ ion was named cuprous ion. Then by the simple rule: name the cation name the anion CuCl₂ was named cupric chloride and CuCl was named cuprous chloride The higher charged ion would end in “ic” and the lower charged ion would end in “ous”.

17. Ionic Compounds II CuCl₂ is named copper(II) chloride and
In the I.U.P.A.C. system
(International Union of Pure and Applied Chemists)
Cu²⁺ ion will be named copper(II) ion and the
Cu⁺ ion will be named copper(I) ion.
Then by the simple rule:
name the cation name the anion
CuCl₂ is named copper(II) chloride and
CuCl is named copper(I) chloride

18. Ionic Compounds II
So the Roman numeral always gives the charge on the ion in type II cations. iron(III) is Fe³⁺ platinum(IV) is Pt⁴⁺ bismuth(V) is Bi⁵⁺ molybdenum(VI) is Mo⁶⁺ rhenium(VII) is Re⁷⁺ osmium(VIII) is Os⁸⁺

19. Ionic Compounds II
Type II cations are all metal ions that are not type I cations. For type II cations the Roman numeral must be given as part of the name of the cation. There is nothing to be memorized. The charge on the ion is given.

20. Write formulas for the following:
titanium(II) oxide
TiO
tin(IV) iodide
SnI₄
antimony(V) sulfide
Sb₂S₅
copper(I) nitride
Cu₃N
gold(III) selenide
Au₂Se₃

21. Names: Ionic Compounds II
Since type II cations need Roman numerals in the name, the charge must be determined from the formula. The charge on the anion will be known. Then since all charges add to zero, the charge on the cation can be determined.

22. Names: Ionic Compounds II
Name the compound: CuO It must have the form copper(__) oxide The oxide always has charge -2 Since copper charge + -2 = 0 It is Cu²⁺ So CuO is copper(II) oxide

23. Names: Ionic Compounds II
Name the compound: CuO A simple way to do this is: Cu O Write charges under the ions x -2 Then x -2 = 0 So x = +2 And CuO is copper(II) oxide

24. Names: Ionic Compounds II
Name the compound: Fe₂S₃ Write x -2 Multiply by the subscripts 2x +(-2)·3 = 0 and set = to zero so x = 3 So Fe₂S₃ is iron(III) sulfide

25. Names: Ionic Compounds II
Name the following:
CrO₃
chromium(VI) oxide
UF₄
uranium(IV) fluoride
Hg₂S
mercury(I) sulfide
Mn₃P₂
manganese(II) phosphide

26. Ionic Compounds III
It was discovered around 1826 that not all ions are monotomic, i.e., single atoms that have gained or lost electrons. The salt NaCN dissolves in water to give sodium ions, Na⁺, and cyanide ions, CN⁻, which consist of carbon and nitrogen (covalently) bonded together and having an extra electron.

27. Ionic Compounds III
Ions that have covalently bonded atoms are called polyatomic ions. Many of them consist of an elements bonded to oxygen atoms and having a negative charge. These ions end in “ate”. Examples are: nitrate NO₃⁻ sulfate SO₄²⁻ phosphate PO₄³⁻ carbonate CO₃²⁻

28. Ionic Compounds III
Besides cyanide, CN⁻, hydroxide, OH⁻, and peroxide, O₂²⁻ are named as ”ide” ions. The ammonium ion, NH₄⁺, is a polyatomic cation. A number of these ions need to be memorized. The following table may be helpful.

29. Notice: odd columns have odd (-1,-3) charges.
The “ate” ions: 4A 5A 6A 7A
CO₃²⁻
NO₃⁻
PO₄³⁻
SO₄²⁻
ClO₃⁻
AsO₄³⁻
SeO₄²⁻
BrO₃⁻
TeO₄²⁻
IO₃⁻
Notice: odd columns have odd (-1,-3) charges.
Even columns (4A,6A) have even charges.

30. Ionic Compounds III
Using the rule: name the cation name the anion to name these compounds. Na₂SO₄ is called sodium sulfate SO₄²⁻ is sulfate Cu(NO₃)₂ is called copper(II) nitrate NO₃⁻ is nitrate Two or more of a polyatomic ion in a compound needs () followed by the subscript. A single polyatomic ion should not have parentheses.