In the modern periodic table what runs horizontally and shows how many electron shells are occupied in the neutral atom in its ground state for the lightest member of that row?
Q1. In the modern periodic table what runs horizontally and shows how many electron shells are occupied in the neutral atom in its ground state for the lightest member of that row?
Answer: A period shows how many shells are filled up to the outermost shell for the first element in that row
Explanation: In the periodic table, periods run horizontally; elements in the same period have the same number of electron shells, with the period number indicating the highest occupied principal quantum number.