Overview
This lecture explains the "language" of chemistry, focusing on ions and acids, their naming rules, and how the Periodic Table helps guide these conventions.
The Language of Chemistry
- Chemistry uses a unique system of names and formulas to communicate information about chemicals.
- Understanding chemical "language" involves learning specific rules for naming elements, ions, and compounds.
Ions: Formation and Naming
- Ions are atoms that gain or lose electrons, resulting in a charge.
- Cations are positively charged ions (lost electrons); anions are negatively charged (gained electrons).
- Monatomic ions are single-atom ions, written with the element symbol plus a superscript charge.
- Cations are named as the element plus "ion" (e.g., sodium ion).
- Anions use the "-ide" suffix (e.g., chloride).
- Ionic compounds are named by stating the cation then the anion (e.g., sodium chloride).
The Periodic Table and Ions
- Alkali and alkaline earth metals (first two columns) typically form cations.
- Halogens, oxygen, sulfur, and nitrogen form common anions ending with "-ide".
- Transition metals can form multiple cations with different charges.
Naming Transition Metals
- Transition metal cations are named using Roman numerals to indicate charge (e.g., Iron(II), Iron(III)), with numerals in parentheses.
Acids: Composition and Naming
- Acids are ionic compounds with hydrogen ions (H⁺) as cations and various anions.
- Acid formulas are written by pairing H⁺ with the corresponding anion (e.g., HClO₃).
- Acid and anion names use prefixes and suffixes to indicate oxygen content.
Acid Naming Rules
- "-ate" anions form acids ending in "-ic" (e.g., chlorate → chloric acid).
- "-ite" anions (one less O) form acids ending in "-ous" (e.g., chlorite → chlorous acid).
- Add "hypo-" for two fewer O (e.g., hypochlorite/hypochlorous acid).
- Add "per-" for one more O (e.g., perchlorate/perchloric acid).
- Acids without oxygen use the "hydro-" prefix and "-ic" (e.g., hydrochloric acid).
Key Terms & Definitions
- Cation — a positively charged ion.
- Anion — a negatively charged ion.
- Monatomic ion — an ion formed from a single atom.
- Transition metal — elements in the middle of the Periodic Table with variable charges.
- Roman numeral naming — indicates the charge of a transition metal cation.
- Acid — compound with hydrogen ions (H⁺) as cations and an anion.
- "-ate", "-ite", "hypo-", "per-" — suffixes/prefixes indicating oxygen quantity in acid anions.
Action Items / Next Steps
- Copy the table of acid/anion naming rules as presented.
- Review common "-ate" ions and their corresponding "-ic" acids.
- Practice naming and writing formulas for ions, transition metals, and acids.