Question

An element has 17 protons and its two isotopes have 18 and 20 neutrons What is the ratio of average atomic mass to atomic no. of this elements if
both isotopes exist equally?​

Answer 1

Answer:

Find tan Alpha when vector product is 16

Answer 2

Answer:

The ratio of average atomic weight to the atomic number of the element is 36:17

Explanation:

Given that,

An element has 17 protons and its two isotopes have 18 and 20 neutrons.

As the element has 17 protons ,its atomic number is 17 $= > Z=17$

Given that one of its isotope has 18 neutrons.Therefore,its mass is

$A_{1}=N_{1}+Z=18+17=35a.m.u$

Other isotope has 20 neutrons.Therefore,its mass is

$A_{2}=N_{2}+Z=20+17=37a.m.u$

Given that both the isotopes exist in equal amount.Let us consider they exist in the ratio 1:1.Therefore the average atomic mass of the element is

$m_{avg}=\frac{A_{1}\times1+A_{2}\times1}{1+1} =\frac{A_{1}+A_{2}}{2}$

Substituting the values of masses of both the isotopes,we get-

$m_{avg}=\frac{37+35}{2} =36a.m.u$

Now the ratio of average atomic weight to the atomic number of the element is

$\frac{m_{avg}}{Z} =\frac{36}{17}$

Therefore,The ratio of average atomic weight to the atomic number of the element is 36:17

#SPJ3