Chemical Nomenclature Lecture Notes

Introduction

Chemical formula: Represents the number of atoms in each compound or molecule.
Molecular compounds: Composed of non-metals.
- Example: C8H18 (8 carbon atoms and 18 hydrogen atoms).

Definition: Consist of cations (from metals) and anions (from non-metals).
- Example: Al2(SO4)3 (2 aluminum atoms and 3 sulfate groups).
Polyatomic ions: Group of atoms with a charge; not found as a single element on the periodic table.
- Sulfate (SO4) is a polyatomic ion.
Subscripts: Distribute across the elements within parentheses (e.g., in Al2(SO4)3, 3 sulfates result in 3 sulfur and 12 oxygen atoms).

Cations: Positively charged ions; metals lose electrons.
Anions: Negatively charged ions; non-metals gain electrons.
Periodic table group charges:
- Group 1: +1
- Group 2: +2
- Group 3: +3
- Group 5: -3
- Group 6: -2
- Group 7: -1
- Transition metals: Variable charges.
Noble gas configuration: Elements gain or lose electrons to achieve a noble gas electron configuration.

Monatomic ions:
- Cations: Same as element name (e.g., K+ = potassium ion).
- Anions: Element name ending in -ide (e.g., F- = fluoride).

Binary Ionic Compounds:
- Composed of 2 elements; cation and anion.
- Charges must cancel out (e.g., MgBr2).
- Crossover method: Cross charges to form subscripts.
- Reduction of subscripts: Reduce numbers when possible (e.g., Ba+2 and C-2 becomes BaC).
Transition Metals:
- Variable charges indicated by Roman numerals (e.g., CuCl2 = Copper (II) chloride).
- Determine charge by balancing with known anion charges.
Polyatomic Ions:
- Have more than one element and a charge.
- Be cautious of similar names/formulas (e.g., nitrate vs nitrite).
Naming Tin(IV) Sulfate:
- Tin = Sn, sulfate = SO4
- Sn2(SO4)4 reduces to Sn(SO4)2.
Binary Molecular Compounds:
- Two non-metals; use prefixes (mono-, di-, tri-, etc.).
- First element: No prefix if one atom.
- Second element: Ends in -ide; avoid double vowels (e.g., monoxide not monooxide).