Formula Clues
This kind of number in C₈H₁₈ tells you how many atoms of an element are in one molecule.
A subscript
A monatomic cation keeps this, instead of changing its ending.
Its element name
Al³⁺ and O²⁻ combine to give this formula unit.
Al₂O₃
NH₄⁺ is this kind of ion: more than one atom, still charged.
A polyatomic ion
In a free element such as Fe or O₂, the oxidation number is this.
0
In Al₂(SO₄)₃, this subscript multiplies everything inside the parentheses.
3
A monatomic anion changes its ending to this.
-ide
Zn²⁺ and I⁻ combine to give this formula unit.
ZnI₂
An oxyanion is a polyatomic ion that contains this element.
Oxygen
Group 1 metals in compounds are assigned this oxidation number.
1
One formula unit of Al₂(SO₄)₃ contains this many oxygen atoms.
12
Fe²⁺ is written this way in a compound name so you know which iron ion it is.
Iron(II)
Ba²⁺ and O²⁻ combine to give this formula unit
BaO
Between nitrite and nitrate, this ending belongs to the ion with more oxygen.
-ate
Oxygen is usually −2, but in a peroxide such as H₂O₂, it is this.
−1
Na⁺ and F⁻ are both this kind of ion, formed from a single atom.
A monatomic ion
CuCl₂ is named this, not just “copper chloride.”
Copper(II) chloride
Sn⁴⁺ and SO₄²⁻ combine to give this formula.
Sn(SO₄)₂
As₂O₅ is named this
Diarsenic pentoxide
Hydrogen is usually +1, except in metal hydrides such as NaH, where it is this.
−1
The 4 in Al₂(SO₄)₃ refers to oxygen atoms in this ion.
The sulfate ion
Hypo- and per- are added when an oxyanion family extends beyond this pair of endings.
-ite and -ate
A formula unit is the simplest ratio that makes total positive charge equal this.
Total negative charge
In a binary molecular name, mono- is left off this element
The first element
Oxidation numbers in a polyatomic ion must add up to this
The ion's charge