Isotopes and relative atomic mass | Chemistry | Quizalize & Oak National Academy

Starter quiz

Which two subatomic particles are present in the nucleus of an atom?
- proton ✓
- electron
- neutron ✓
The relative mass of a neutron is ______.
- 'one' ✓
What is the mass number of an atom?
- number of protons
- total number of protons and neutrons ✓
- number of neutrons
- total number of protons and electrons
- number of electrons
Order the method for working out the number of the three subatomic particles in an atom of sodium. Start with the number of protons, then work out the number of electrons, then finally neutrons.
- 1
  
  ⇔
  
  number of protons = atomic number or proton number, for sodium = 11
- 2
  
  ⇔
  
  number of electrons = same as the number of protons, for sodium = 11
- 3
  
  ⇔
  
  mass number = total number of protons + neutrons
- 4
  
  ⇔
  
  number of neutrons = mass number - number of protons, for sodium: 23 - 11 = 12
Match the atoms with the number of neutrons in their nucleus. Use your periodic table to help.
- ¹⁴N
  
  ⇔
  
  7 ✓
- ¹⁹F
  
  ⇔
  
  10 ✓
- ⁴⁰Ca
  
  ⇔
  
  20 ✓
- ⁴⁰Ar
  
  ⇔
  
  22 ✓
- ⁷Li
  
  ⇔
  
  4 ✓
- ¹⁶O
  
  ⇔
  
  8 ✓
Chlorine atoms mainly exist as ³⁵Cl and ³⁷Cl. Why are the mass numbers different?
- They should all be the same.
- ³⁵Cl has 18 protons and ³⁷Cl has 20 protons.
- ³⁷Cl has gained two electrons to get a full outer shell.
- ³⁵Cl has 18 neutrons and ³⁷Cl has 20 protons.
- ³⁵Cl has 18 neutrons and ³⁷Cl has 20 neutrons. ✓