Question

Calculate number of neutrons present in 12*10^25 atoms of oxygen whose atomic no. is 8 and mass no. is 17 (Given: Na =6*10^23)

Answer 1

Hey mate !!

Here's the answer !!

We know that Atomic mass is the sum of number of protons and neutrons.

We also know that atomic number is equal to the number of protons.

Hence,

Atomic number = Number of Protons 

=> Atomic number = 8 = Number of protons

Also,

Mass number = Number of Protons + Number of neutrons

We know that mass number is 17 according to the question. Hence substituting we get,

17 = 8 + Number of Neutrons

=> Number of neutrons = 17 - 8 = 9 neutrons.

To calculate total number of neutrons in 12 × 10²⁵ atoms of Oxygen.

Therefore total number of neutrons = 9 × 12 × 10²⁵

= 108 × 10²⁵ neutrons.

We also know that Na = 6 × 10²³ atoms.

In terms of Na we can write it as:

= 108 × 10²⁵ / 6 × 10²³

= 18 × 10²

= 1800 Na

Note : The actual Mass number of Oxygen is 16 but due to the given information I have used and did using 17 as the mass number.

Hope my answer helps !!

Cheers !!

Answer 2

Answer:

1800Na

Explanation:

Atomic number =8

N=17-8=9

no of neutrons = 9*12*10^25

= 9*12*10^25/6*10^23

=1800Na