Atoms

relative atomic mass

Atoms

particles

charge

size

98.9% of carbon is carbon-12

1.1% of carbon is carbon-13

What are the amount of protons, neutrons and electrons in each of these?

(% of isotope 1 × mass of isotope 1) + (% of isotope 2 × mass of isotope 2)

100

Calculate the number of protons, electrons and neutron in each of these:

Sodium, potassium, nitrogen, oxygen, iron, tungsten, lead, phosphorus

Electron shells

The electrons are arranged into shells

2 in the first shell

8 in the second shell

8 in the third shell