I am aware of a few possibilities.
Most common, probably, is that something is without a set period so it doesn't transpire transpire or occur or whatever in a specific temporal manner.
Another, and probably uncommon, possibility is that something is not of the periodic elements...but such use would probably only occur in very rare instances like perhaps in a Science Fiction story where the author is explaining that something is of alien origin because it is composed of non-periodic elements.
non periodic change
What is your definition of slow? Minutes, years, eons? Some that might do: slow and periodic: the progression of the seasons fast and non-periodic: an explosion fast and periodic: the swing of a pendulum slow and non-periodic: the weathering of rocks.
Non periodic change is game and business
Irregular and non-periodic vibration produce noise.
Non-metals and metalloids are found to the right on the periodic table.
a repetitivemotion,which repeats itself ,but not at fixed intervals of time's called as non periodic motion
A non-repetitive pattern.
Hydrogen can be considered as a non metal. It is placed to the left of the periodic table.
The periodic table comprises of metals (on the left) ,non-metals(on the right ) and transition elements (between metals and non-metals) in the periodic table.
yes, families and groups the same meaning in the periodic table.
Periodic changes are those changes that repeat themselves at frequent intervals of time. Non periodic changes are those changes that do not repeat themselves at regular intervals of time
See related link for a list of periodic and non periodic comets.