Question

4 group the labels according to the arrangement of elements they describe. vertical columns based on reactions number of electron shells horizontal row alkaline - earth metals lithium through neon period group both

Explanation:

In the periodic table, periods are horizontal rows and groups are vertical columns. "Vertical columns" and "Alkaline - earth metals" (which are in a specific group) describe groups. "Horizontal row" and "Lithium through neon" (which are in a specific period) describe periods. "Based on sections" and "Number of electron shells" can relate to both as they are properties that vary across periods and groups.

Answer:

Period: Horizontal row, Lithium through neon
Both: Based on sections, Number of electron shells
Group: Vertical columns, Alkaline - earth metals