Advertisements
Advertisements
Question
Explain why, the atomic masses of many elements are in fractions and not whole numbers.
Solution
The mass of an atom of any natural element is taken as the average mass of all the naturally-occurring atoms of that element. If an element has no isotopes, then the mass of its atom would be the same as the sum of the protons and neutrons in it. But if an element occurs in isotopic forms, then we have to know the percentage of each isotopic form and then calculate the average mass.
Average Atomic Mass of Chlorine = `35 xx[75/100]+37[25/100]`
= `2625/100+ 925/100`
= 26.25 + 9.25
= 35.5 u
Therefore, the masses of certain elements are in fractions and not whole numbers.
APPEARS IN
RELATED QUESTIONS
What name is given to those isotopes which have unstable nuclei and emit various types of radiations ?
What is the reason for the different atomic masses of the isotopes of an element ?
(a) What are radioactive isotopes ? Give two examples of radioactive isotopes.
(b) Give any two uses of radioactive isotopes.
(c) An element Z contains two naturally occurring isotopes `""_17^35"Z"` and `""_17^37"Z"`. If the average atomic mass of this element be 35.5 u, calculate the percentage of two isotopes.
The radioactive isotope used in the treatment of cancer is :
The isotopes of an element contain :
What are isotones? Give one example.
U-235 Isotope is used as ______.
List the uses of isotopes.
Distinguish isotopes from isobar
How is the radioactivity of a radio isotope affected if it undergoes a chemical change? Give a reason for your answer.
