Atomic Structure

State Symbols used in Chemical Equations.

The equations from the two previous pages
(3)    2K  +  Cl₂     2KCl
 (4)   4Li  +  O₂     2Li₂O
still require state symbols to be complete.

The complete equations in words and symbols would be
potassium + chlorine  potassium chloride.
2K_(s)  +    Cl_2(g)              2KCl_(s)

lithium + oxygen  lithium oxide.
4Li_(s)  +    O_2(g)          2Li₂O_(s)

The state symbols in brackets show the physical state of the substance
at the reaction temperature.
Solid (s), liquid (l), gas (g), or dissolved in water (aq).
aq is called aqueous which comes from the Latin word aqua meaning water.

If you do not know the state of a substance see melting and boiling points.

If the melting point is above the reaction temperature,
the substance is solid (s).

If the boiling point is below the reaction temperature,
the substance is gas (g).

If the melting point is below the reaction temperature
and the boiling point is above the reaction temperature,
then the substance is liquid (l).

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