C1 Particles

Question 1

How are particles in a solid arranged?

Answer 1

They do not move from their positions as they all keep a definite shape and volume (in a fixed position)

Question 2

What structure do particles in a solid have?

Answer 2

There are strong forces of attraction between particles in a very regular lattice arrangement.

Question 3

How are the particles in a liquid arranged?

Answer 3

They are constantly moving with random motion but they tend to stick together and they do not keep a definite shape but they keep the same volume.

Question 4

What are the forces of attraction like in a liquid?

Answer 4

There is some force of attraction between the particles but they’re free to move past and alongside each other.

Question 5

How does a high temperature effect particles in a liquid?

Answer 5

The hotter the liquid gets, the faster they move- causing the liquid to expand. If the liquid becomes too hot, it will evaporate and become a gas.

Question 6

How does a low temperature effect particles in a liquid?

Answer 6

If the temperature gets too cold, the liquid will freeze and become a solid.

Question 7

How are the particles in a gas arranged?

Answer 7

They do not have a definite shape or volume. They are free to move and they have a lot of kinetic energy. When they bounce off the walls of a container, the exert a pressure on the walls.

Question 8

What are the forces of attraction like in a gas?

Answer 8

There’s next to no force of attraction between the particles as they are free to move anywhere. They travel in straight lines and only interact when they collide. There’s next to no force of attraction between the particles as they are free to move anywhere. They travel in straight lines and only interact when they collide.

Question 9

How does a high temperature effect particles in a solid?

Answer 9

The hotter the solid becomes, the more the particles vibrate- causing solids to expand slightly when heated. Eventually they will melt and become a liquid.

Question 10

How does a high temperature effect particles in a gas?

Answer 10

The hotter the gas gets, the faster they move and they will either expand or their pressure will increase when heated.

Question 11

How does a low temperature effect particles in a gas?

Answer 11

If the temperature gets too cold, the gas condenses and becomes a liquid.

Question 12

What is an advantage of the particle model?

Answer 12

It is a great model for explaining the three states of matter.

Question 13

What is a disadvantage of the particle theory?

Answer 13

The model does not show any of the forces between the particles so there is no way of knowing how strong the forces are.

Question 14

What is a physical change?

Answer 14

A physical change is when a substance changes from one state of matter to another.

Question 15

What is a chemical change?

Answer 15

A chemical change is when bonds between atoms break and the atoms change places. The atoms in the substance you start with re-arrange themselves to form different chemicals. They are often hard to reverse.

Question 16

Who, in the 19th century, described atoms as ‘solid spheres’?

Answer 16

John Dalton describes atoms as solid spheres and said that different spheres made up the different elements.

Question 17

Who concluded that atoms were not solid spheres in 1897?

Answer 17

JJ Thomson. His measurements of charge and mass showed that an atom must contain even smaller, negatively charged particles (electrons).

Question 18

What did JJ Thomson name his new theory that proved the ‘solid sphere’ theory wrong?

Answer 18

The Plum Pudding Model

Question 19

Who conducted the gold foil experiment in 1909?

Answer 19

Ernest Rutherford and his students: Hans Geiger and Ernest Marsden

Question 20

What was the gold foil experiment?

Answer 20

Ernest Rutherford and his students fired positively charged alpha particles at an extremely thin sheet of gold.

Question 21

What happened to the alpha particles when they were fired at the sheet of gold?

Answer 21

Most of the particles went straight through the gold sheet, but some were deflected more than expected, and a small number were deflected backwards.

Question 22

What did Rutherford name his theory that proved the plum pudding model wrong?

Answer 22

The Nuclear Atom Theory

Question 23

What is the nuclear atom theory?

Answer 23

That there is a tiny positively charged nucleus at the centre, surrounded by a ‘cloud’ of negative electrons and that the atom was mostly empty space.

Question 24

What was the Plum Pudding Model?

Answer 24

The Plum Pudding Model showed that atoms must contain even smaller, negatively charged particles (electrons).

Question 25

What did Niels Bohr propose?

Answer 25

Bohr suggested that electrons can only exist in fixed orbits (shells) and not anywhere in between and each shell has a fixed energy.

Question 26

What supported Bohr’s theory?

Answer 26

Bohr’s theory was supported by many experiments and it helped to explain other scientists’ observations at the time. It is pretty close to the current version of the atom.

Question 27

What is the relative mass of a proton?

Answer 27

1

Question 28

What is the relative charge of a proton?

Answer 28

+1

Question 29

What is the relative mass of a neutron?

Answer 29

1

Question 30

What is the relative charge of a neutron?

Answer 30

0

Question 31

What is the relative mass of an electron?

Answer 31

0.0005 (negligible)

Question 32

What is the relative charge of an electron?

Answer 32

-1

Question 33

Where is the nucleus found in an atom?

Answer 33

It is located in the middle of the atom

Question 34

What does the nucleus contain?

Answer 34

Protons and Neutrons

Question 35

What charge does the nucleus have?

Answer 35

A positive charge because of the protons

Question 36

What is the whole mass of an atom?

Answer 36

…

Question 37

What is the size of a nucleus’ radius?

Answer 37

0.073nm

Question 38

Where are electrons found in the atom?

Answer 38

Electrons orbit around the nucleus in shells