Question

who relative atomic mass calculated full information

Answer 1

Some elements have been found to contain isotopes. The relative atomic mass of such element is determined by the masses of all the isotopes, and is closer to the mass of the more abundant isotope.

The relative atomic mass of these elements can be calculated using the formula:

Relative atomic mass = (A/100 x a) + (B/100 x b) + (C/100 x c)

Where A/100 (or A%) is the abundance of one of the isotopes with relative atomic mass a; B/100 is the abundance of another isotope with relative atomic mass b; C/100 is the abundance of the third isotope with relative atomic mass c.

Example 1: Oxygen has three isotopes 16O, 17O, and 18O with relative abundance 99.76%, 0.04%, and 0.20% respectively, calculate the relative atomic mass of oxygen.

Solution:

Relative atomic mass of 16O is 16 and its relative abundance is 99.76%; 17O – atomic mass 17, abundance 0.04%; 18O – atomic mass 18, abundance 0.20%.

Relative atomic mass of oxygen = (99.76/100 x 16) + (0.04/100 x 17) + (0.20/100 x 18)

 = 15.9616 + 0.0068 + 0.036 = 16.0044

Answer 2

relative atomic mass= number of protons + number of neutrons
for example
relative atomic mass of oxygen=8 protons +8neutrons=16 atomic mass