Periodic law
The law stating that the chemical properties of an element depend on the atomic number of the
element, and change in a periodic fashion.
Periodic table
Periodic table
The table displaying all known chemical elements arranged in rows (periods) and columns
(groups) according to their electronic structure.
pH
pH
A measure of the hydrogen ion content of an aqueous solution, defined to be equal to the
negative log of the H+ concentration.
Phase
Phase
One of the three states of matter: solid, liquid, or gas. (Plasma is often considered a fourth phase
of matter.)
Phase diagram
Phase diagram
A plot, usually of pressure versus temperature, showing which phases a compound will exhibit
under any set of conditions.
Phase equilibrium
Phase equilibrium
For a particular substance, any temperature and pressure at which two or three phases coexist in
equilibrium. See Triple point.