L2- Developing Understanding Of More Complicated Models.

Question 1

What was Rutherford’s model?

Answer 1

He believed an atom was made of a tiny, positively charged nucleus, that contained almost all the mass, and that atoms had electrons around the outside. However, his model meant that eventually, electrons should lose energy and fall into the nucleus.

Question 2

Name the issues with Thomson’s plum-pudding model.

Answer 2

If the plum pudding model had been correct then all of the fast, highly charged alpha particles in Rutherford’s experiment would have whizzed straight through undeflected. However, some of the particles were deflected by the dense nucleus.

Question 3

Name three results of Rutherford’s experiment and briefly explain the causes.

Answer 3

1) One in eight thousand alpha particles bounced back- dense nucleus.
2) Some were deflected at large angles- repelled from nucleus’ positive charge.
3) Some atoms went through- therefore atom has empty space.

Question 4

What was the Bohr model and when was it developed?

Answer 4

In 1913, Niels Bohr suggested that electrons can only move in fixed orbits, called electron shells, around the nucleus. The Bohr model of the atom has been improved over the past century, but it still provides a good basis for imagining how protons, neutrons, and electrons in atoms are arranged.

Question 5

What is the size of an atom?

Answer 5

1 x 10-10m.

Question 6

What is the size of the nucleus of an atom?

Answer 6

1 x 10-15

Question 7

Define what the key word “molecule” means.

Answer 7

Molecules are a collection of atoms, strongly joined together, or bonded.

Question 8

Define what the term “magnitude estimation” means.

Answer 8

An example is the size of an atom, because it is a term that only involves a power of ten.

Question 9

Name differences between all the models.

Answer 9

1) Dalton’s model is a small, indestructible sphere and has no neutrons/electrons/protons.
2) However, Thomson’s model has electrons and positive mass.
3) Additionally, Rutherford’s model has a dense nucleus of positive mass/electron/confirmed empty space.
4) Bohr’s model differs from Rutherford’s, as his would lead to electrons spiralling inwards on one another. Unlike all, it has set orbits for electron shells.

Question 10

Name the two scientists that worked alongside Rutherford?

Answer 10

Hans Geiger and Ernest Marsden.