11 15
Atoms were thought to be particles that could not be divided up into smaller particles.
By 1898, the electron had been discovered and the plum-pudding model of an
atom was proposed.
The results from experiments after 1898 led to the nuclear model.
Compare the position of the subatomic particles in the plum-pudding and nuclear
models.
[4 marks]

Achemical equilibrium between gaseous reactants and products is shown. n2(g) + 3h2(g) ⇌ 2nh3(g) how will the reaction be affected if the pressure on the system is increased? it will shift toward the reactant side as there is lower pressure on the reactant side. it will shift toward the product side as there is higher pressure on the product side. it will shift toward the reactant side as there are a greater number of moles of gas on the reactant side. it will shift toward the product side as there are a fewer number of moles of gas on the product side.