2.1.1 Atomic Structure And Isotopes

Question 1

What is the relative isotopic mass?

Answer 1

The mass of one atom or element compared with one twelfth of the mass of an atom of carbon

Question 2

What is the relative atomic mass?

Answer 2

The average mass of 1 atom divided by mass of 1/12th atom of 12C

Question 3

What is the relative molecular mass?

Answer 3

The mass of 1 molecule of the compound divided by the mass of 1/12th atom of 12C

Question 4

What is an isotope?

Answer 4

Atoms of the same element with different numbers of neutrons and different masses

Question 5

How to calculate relative formula mass from relative atomic mass?

Answer 5

The sum of all of the atomic masses of each element present in the formula

Question 6

How to calculate relative atomic mass?

Answer 6

(Relative abundance 1 x mass 1) + (relative abundance 2 x mass 2)
/ 100

Question 7

What is the purpose of a mass spectrometer?

Answer 7

It can find the percentage abundance of isotopes in an element

Question 8

How does a mass spectrometer work (basic)?

Answer 8

• sample vaporised
• sample ionised to form +ve ions
• ions accelerated (heavy ions slower/less deflected)
• ions detected as mass to charge ratio (each produces a signal so larger signal greater abundance)
• mass spectra produced can be used to calculate relative atomic mass