Exam practise Flashcards
(7 cards)
Chadwick’s experimental work on the atom led to a better understanding of
isotopes.
Explain how his work led to this understanding.
Chadwick discovered the neutron.
This is important because isotopes are elements with the same number of protons, but different number of neutrons.
The plum pudding model suggested that the atom was a ball of positive
charge with electrons embedded in it.
Evidence from the alpha particle scattering experiment led to a change in
the model of the atom from the plum pudding model.
Explain how.
Most of the alpha particles passed through the gold foil, so most of the most of the atom is concentrated in the nucleus.
Some alpha particles were deflected/bounced back, so proves that the atom has a positively charged nucleus.
Explain why sodium oxide has a high melting point.
It is a giant lattice structure.
There are strong electrostatic forces between the oppositely charged ions which require lots of energy to break.
Niels Bohr adapted the nuclear model.
Describe the change that Bohr made to the nuclear model.
- electrons orbit the nucleus
- at specific distances from the nucleus
Explain the trend in boiling points of the halogens.
As you go down the group, the boiling point increases
as you go down the group, molecular mass increases, so the intermolecular forces are stronger
so more energy is needed to break the intermolecular foeces
Why did Mendeleev’s periodic table become more widely accepted than
previous versions?
He predicted the properties of the missing elements.
Then those missing elements were discovered and filled in the gaps
Mendeleev’s prediction matched the properties of those elements.
Chlorine reacts with hydrogen to form hydrogen chloride.
Explain why hydrogen chloride is a gas at room temperature.
Answer in terms of structure and bonding.
It is a simple covalent structure.
It has weak intermolecular forces, which require less energy to break.
