Answer:
periodic
Explanation:
Elements are organised in the periodic table of elements, which is essentially a big table that lists elements in order by increasing atomic number and atomic mass.
Each row of a periodic table is called a 'period', and when elements are arranged in the above-described way, there is a repeating pattern because each column has elements that share properties. So as you move across a period (or row), you get elements of different properties, but as you move across another period, you get different elements with similar properties as before.
Thus, it's periodic.
