Isotopes

Question 1

What is an isotope?

Answer 1

• Forms of elements with different numbers of neutrons to protons
• Same chemical properties
• Density can differ.

Question 2

Formula for relative atomic mass of an isotope:

Answer 2

Relative atomic mass (Ar) = 
sum of (isotope abundance X isotope mass number) / sum of abundance of all the isotopes

Question 3

Copper has two stable isotopes. Cu-63 has an abundance of 69.2% and Cu-65 has an abundance of 30.8%. Calculate the relative atomic mass of copper to 1dp.

Answer 3

Ar = (69.2 X 63) + (30.8 X 65) / (69.2 + 30.8)
= 4359.6 + 2002 / 100
= 6361.6 / 100
= 63.616 
= 63.6