Question

find argon on the periodic table and provide the number of protons, neutrons, and electrons.
18 protons, 18 electrons, 40 neutrons
9 protons, 9 electrons, 9 neutrons
18 protons, 18 electrons, 22 neutrons
40 protons, 9 electrons, 9 neutrons
9 protons, 40 electrons, 18 neutrons

Explanation:

Step1: Get argon's atomic number

Argon (Ar) has an atomic number $Z=18$, so protons = electrons = 18.

Step2: Get argon's mass number

The most common isotope of argon is $^{40}\text{Ar}$, mass number $A=40$.

Step3: Calculate neutron count

Neutrons = $A-Z = 40-18=22$.

Answer:

18 protons, 18 electrons, 22 neutrons