Question

why periodic table not called a chart

Answer 1

Answer:

Mendeleev realized that the physical and chemical properties of elements were related to their atomic mass in a 'periodic' way, and arranged them so that groups of elements with similar properties fell into vertical columns in his table.

Answer 2

Answer:

It is called the periodic table because of the way the elements are arranged. You'll notice they're in rows and columns. The horizontal rows (which go from left to right) are called 'periods' and the vertical columns (going from up to down) are called 'groups'.