Question

the number in each square of the periodic table tells us the atomic number of each element. which element is number 18? oxygen (o) argon (ar) aluminum (al)

Explanation:

To determine the element with atomic number 18, we recall the periodic table: Oxygen (O) has atomic number 8, Aluminum (Al) has atomic number 13, and Argon (Ar) has atomic number 18.

Answer:

B. Argon (Ar)