1813

Chemical nomenclature

• Chemical notation began with alchemists
• who associated each known metal with a planet
• and so used the planetary symbols for them.
• In 1787, Antoine Lavoisier proposed
• naming compounds by class and species,
• similar to Linnaeus’s system for plants and animals.
• After 1808, the state of art for describing
• chemical elements and their compounds
• were diagrams using John Dalton’s circular symbols.
• Today, the International Union
• of Pure and Applied Chemistry maintains
• modern rules and standards for chemical nomenclature.
• This system began with a proposal
• by Jöns Jacob Berzelius suggesting
• instead of diagrams, using letters and numbers—
• the letters to be based on the Latin names
• of the elements, and the numbers
• to show their proportions in a compound.

Differences

• Between symbols, Berzelius used plus signs
• for elements in a compound
• except for compounds “of first order.”
• To show proportions in compounds, Berzelius
• placed a number above the element symbol;
• today we use a subscript.
• It is also common today to place a superscript
• with a plus or minus sign to show the charge,
• the balance of protons and electrons.
• *
• The symbol for potassium is K
• because the Germans, including Berzelius,
• preferred the Latin name kalium.
• Tungsten was discovered in two minerals,
• tungsten and wolframite, and it has two names,
• tungsten and wolfram, with the symbol W.

Symbols

• A symbol may represent anything,
• but most symbols we see every day
• are mainly graphic mnemonics, because
• one can often see a cockeyed correspondence.
• The symbol at the men’s room wears pants;
• well, so do women, and men wear skirts.
• The symbols on a switch are O and |,
• one of which means on, and the other off.
• The meanings of hieroglyphs were lost
• even though they had been written in stone.