C1 - Particles

Question 1

What are the states of matter and particles?

Answer 1

Solids: Closely packed particles
They are in a regular arrangement
They vibrate on the spot
Liquids: Definite volume but not shape
Flow to fill the shape of container
Particles move around each other
Particles are constantly moving in
random motion
Gas: Particles move fast and in all directions
Far apart in in random arrangement

Question 2

What is the sequence of scientists in the ‘History of the atom’?

Answer 2

Dalton - atoms were the smallest particles
- Atoms cannot be split
JJ Thomson - discovered electron
- Plum pudding model ( negatively charged electrons within ball of positive mass.
Rutherford - Discovered nucleus
- Gold foil experiment ( shot alpha particles at sheet of gold foil ,most went through however some deflected concluding there is a ball of positive mass at centre of atoms.
Bohr - Discovered electrons orbit nucleus at fixed energy levels / shells.

Question 3

The atom

• diameter size
• where subatomic particles are found
• subatomic particles -> mass and charges

Answer 3

ATOM: 1 x 10^-10 m in diametre
Nucleus –> Protons and Neutrons
Shells–> Electrons

Proton - Relative mass = 1 
              Relative charge = +1
Electron - Relative mass = 0.0005
               -Relative charge = -1
Neutron - Relative mass = 1
               - Relative charge = 0

Question 4

What is an ion?

Answer 4

Ion: Charged particles which have either lost or gained electrons.

Question 5

What is an Isotope?

Answer 5

Isotopes: Atoms of the same element with the same number of protons but different number of neutrons (Different mass numbers)

Question 6

What is the mass number and atomic number?

Answer 6

Mass number : number of protons and neutrons

Atomic number: Number of protons

Question 7

Limitations of the particles model?

Answer 7

• In reality atoms are not spheres
• No forces are represented
• Gives no idea on size and space between particles