Answer:
B.18 protons 22 neutrons 18 electrons
Step-by-step explanation:
Neutral atom of Argon;
Atomic mass = 40amu
Atomic number = 18
Let us find the number of the subatomic particles;
Protons are the positively charged particles in an atom
Electrons are the negatively charged particles
Neutrons do not carry any charges.
Now;
Atomic mass = number of protons + number of neutrons
Atomic number = number of protons
number of protons = 18
In a neutral atom, number of protons equals number of electrons
number of electrons = 18
Number of neutrons = atomic mass - atomic number
Number of neutrons = 40 - 18 = 22
18 protons, 18 electrons and 22 neutrons