Question

1. elements in a__________have similar chemical properties. a period b group c row

Explanation:

In the periodic table, elements in the same group (vertical column) have similar chemical properties because they have the same number of valence electrons. Valence electrons are crucial in determining an element's chemical behavior. For example, the alkali metals (Group 1) all have one valence electron and exhibit similar reactivity. In contrast, elements in a period (horizontal row) have different chemical properties as their valence electron count changes across the period. A row is just another name for a period.

Answer:

B. group