Group (of elements)

In chemistry, a group (or family) is a column of elements in the periodic table that share similar properties because they have the same number of electrons in their outermost shell. This similarity influences their behavior and reactions. For example, elements in Group 1, like sodium and potassium, are highly reactive metals, while Group 17 elements, like chlorine and bromine, are reactive nonmetals. Knowing an element's group helps predict its characteristics and how it might interact with other elements.