Chapter 2 Key Concepts

Question 1

Differences in the chemical reactions of isotopes of the same element

Answer 1

• same number of electrons. Electrons are responsible for the chemical properties of an element
• number of neutrons has no effect on the reactions of an element
• different isotopes react in the same way

Question 2

Differences in physical properties of isotopes of an element

Answer 2

May be a small difference in physical properties eg

Higher mass isotopes have a
higher melting point
higher boiling point
Higher density

Question 3

Use of mass spec

Answer 3

Determine RIM and the relative abundance’s of those isotopes

Calculate RAM of an element from the relative abundances of its isotopes

Question 4

How does a mass spectrometer work?

Answer 4

• Place sample into mass spec
• vaporise and ionise to make positive ions
• accelerate (heavier Ines move slower&more difficult to deflect) so ions are separated
• detect ions in a m/z. Greater the abundance of ions reaching detector means larger signal