Why is chlorine mass number 35.5?

Answer 1

• Example 1.2: chlorine consists of 75% chlorine-35 and 25% chlorine-37.
• ** Think of the data based on 100 atoms, so 75 have a mass of 35 and 25 atoms have a mass of 37.
  • The average mass = [ (75 x 35) + (25 x 37) ] / 100 = 35.5
  • So the relative Atomic Mass of chlorine is 35.5 or Ar(Cl) = 35.5

    because of isotopes.

    there is 75% Cl with mass number 35 and 25% with mass number 37

    so 35 x 3/4 + 37 x 1/4 = 35.5

Answer 2

its mass number is 35.5 because its an average value! some are 35 and some are 37, but overall, the average is 35.5, which tells you that there are more 35 mass numbers than 37! Some mathematics should be done to work it out accurately.

Answer 3

The element chlorine has the atomic number 17, because the atom of chlorine has 17 protons exactly. You have confused this with atomic mass. The atomic mass of chlorine is approximately 35.5; this figure is arrived at by weighing chlorine and getting an average atomic weight. Not all chlorine atoms have the same weight, because although they all contain exactly 17 protons, they do not all have exactly the same number of neutrons. Some have 18 neutrons and some have 19 neutrons. So the average atomic weight determined by the sum of protons and neutrons turns out to be about 35.5 because of the proportion of isotopes that chlorine has here on Earth.

Answer 4

The relative atomic mass is calculated from the percentage of the stabil isotopes around us. With chlorine, these isotopes are:

35Cl --- 75.53%

37Cl --- 24.47%

So, the relative atomic mass is:

(75.53*35 + 24.47 * 37) / 100, which is equal to 35.4894. And we round that to 35.5.

Answer 5

The atomic mass of an element is actually a weighted average of all of the isotopes that make it up. An isotope is like a different version of an atom, having the same number of protons and electrons, but a different number of neutrons. As the natural occurrence of an isotope increases, so does its contribution to the overall average.

The two main kinds of chlorine are chlorine-35 and chlorine-37. In nature you find about three chlorine-35 atoms for every one chlorine-37. When you crunch the numbers to calculate a weighted average, you get 35.5.

Answer 6

This result from a calculus, considering the atomic masses and concentrations of natural chlorine isotopes:

35Cl: 75,77 % and 34,968 852 68 amu.

37Cl: 20,23 % and 36,965 902 59 amu.

Answer 7

Chlorine is found in nature as a mixture of two isotopes: 35Cl (about 76%) and 37Cl (about 24%). The average of the two is the mass on the table.

Answer 8

It is the 'weighted' average mass if both stable naturally occurring isotopes of

Chlorine: 35 and 37 (25% resp. 75%)

Answer 9

That is average mass of chlorine. Chlorine is a gas halogen. Mass number of it is 35.