Question

three features of modern periodic table?​

Answer 1

Explanation:

An urban area, or built-up area, is a human settlement with a high population density and infrastructure of built environment. Urban areas are created through urbanization and are categorized by urban morphology as cities, towns, conurbations or suburbs.

Answer 2

Answer:

Elements are arranged in the increasing order of atomic numbers. Elements in the modern periodic table are arranged in 7 periods and 18 groups. Horizontal rows are called periods and vertical columns are called groups. Elements are placed on periods based on the number of shells in their atoms.