The average atomic mass of a sample of an element X is 16.2 u. What are the percentages of isotopes 8X16 and 8X18 in the sample?

Question

Asked by Vishal kumar | 2 years ago | 229

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Class 9 Science Structure of the Atom Add Answer

Class 9 Science Structure of the Atom View Answer

Which one of the following is a correct electronic configuration of Sodium?

(a) 2, 8

(b) 8, 2, 1

(c) 2, 1, 8

(d) 2, 8, 1

Class 9 Science Structure of the Atom View Answer

Number of valence electrons in Cl– ion are:

(a) 16

(b) 8

(c) 17

(d) 18

Class 9 Science Structure of the Atom View Answer

Isotopes of an element have

(a) The same physical properties

(b) Different chemical properties

(c) Different number of neutrons

(d) Different atomic numbers.

Class 9 Science Structure of the Atom View Answer

Rutherford’s alpha – particle scattering experiment was responsible for the discovery of

(a) Atomic nucleus

(b) Electron

(c) Proton

(d) Neutron

Class 9 Science Structure of the Atom View Answer

Accepted Answer

Let the percentage of ₈X¹⁶ be ‘a’ and that of ₈X ¹⁸ be ‘100-a’.

As per given data,

16.2u = 16 a / 100 + 18 (100-a) /100

1620 = 16a + 1800 - 18a

1620 = 1800 - 2a

a = 90%

Hence, the percentage of isotope in the sample ₈X¹⁶ is 90% and that of ₈X¹⁸ = 100-a = 100- 90=10%

Answered by Shivani Kumari | 2 years ago