Question

Argon has 3 naturally occurring isotopes , Ar 36, Ar 38, and Ar 40. What is the mass # of each and how many protons, neutrons, and electrons are present in each?

Answer 1

Answer:

Ar 36:  Mass number 36,  18 Protons,  18 neutrons and 18 electrons.

Ar 38:  Mass number 38,  18 Protons,  20 neutrons and 18 electrons.

Ar 40:  Mass number 40,  18 Protons,  22 neutrons and 18 electrons.

Explanation:

The number given after 'Ar'  is the mass number.

The atomic number of Argon is 18 which means that 18 protons and 18 electrons are in the atom of Argon. The mass number of an isotope = number of protons + the number of neutrons.

Answer 2

Argon has 3 isotopes Ar36, Ar38, Ar40

See No of protons is always equal to no of electrons As we are talking about neutral atom

Ar 36

Now mass no =36

As Generally we know Atomic no = mass no/2

=36/2= 18 So it fits in This element also

So no of electrons = no of protons =18

Now As mass no = no of protons + no of neutrons

So, No of neutrons =mass no - no of protons

=36-18= 18

As 18 electrons and 18 protons remains same for other isotopes

Now Let's calculate no of neutrons in other isotopes

No of neutrons in Ar38= 38-18= 20

No of neutrons in Ar40= 40-18= 22

Thanks :-)