C1 Particles Flashcards
How particles in a solid are arranged
Fixed shape
Fixed volume
Fixed position
What structure do particles in a solid have
Strong forces of attraction between particles in a regular lattice arrangement
How are particles in a liquid arranged
Constantly moving with random motion
Stick together
Do not keep a definite shape
Keep the same volume
What are forces of attraction like in a liquid
Strong forces of attraction between particles
Free to move around each other
How a high temperature effects particles in a liquid
Hotter it gets, faster particles move
Causes liquid to expand
if gets too hot, evaporates and becomes a gas.
How a low temperature affects particles in a liquid
Freezes
Becomes solid
How are particles in a gas arranged
No fixed shape or volume
Free to move around
Lot of kinetic energy
When they bounce off the walls of their container they exert pressure on the walls.
What are the forces of attraction like in gases
NO force of attraction between particles
Travel in straight lines and only interact when they collide
How a high temperature affects particles in solids
The hotter, the more the particles vibrate causing solid to expand slightly
Eventually they melt and become a liquid
How high temperature affects particles in gases
The hotter the gas gets the faster the particles of the gas will move and they will either expand and pressure will increase when heated
How a low temperature affects particles in gases
If temperature too cold, gas condenses and turns into liquid
Advantage of particle model
Good model for explaining the 3 states of matter
Disadvantage of particle model
Model doesn’t show any of the FORCES between the particles so there is no way of knowing how strong forces are
Physical change
When a substance changes from 1 state of matter to another
Number of particles does not change
Chemical change
Bonds break between atoms
Number of particles changes
Particles rearrange themselves to form different chemical.
Often hard to reverse
Who described atoms as “solid spheres”
John Dalton
Who concluded that atoms were not solid spheres in 1897 (plum pudding model)
JJ Thomson
Rutherford proved plum pudding model wrong with the unclear atom theory
Who conducted gold foil experiment in 1909
Ernest Rutherford, Hens Geiger, Ernest Marsden
RUTHERFORD CONCLUDED ATOMS HAVE A NUCLEUS
What was gold foil experiment
Positively charged alpha particles fired at an extremely thin sheet of gold.
Most alpha particles went straight through but some were deflected more than expected, and a small number were deflected backwards.
Nuclear atom theory
There is a tiny positively charged nucleus at the center surrounded by a “cloud” of negative electrons.
Atom was mostly space
Plum pudding model
Atoms contain small negatively charged particles/electrons in a ball of positive charge
Bohr model
Electrons orbit nucleus in energy shells, no fixed energy between shells.
Theory supported by many experiments - helped to explain other scientist’s observations at the time.
Closest to the current version of the atom.
Proton relative mass and charge
Mass: 1
Charge: +
Relative mass and charge of a neutron
Mass: 1
Charge: 0
Relative mass and charge of an electron:
Mass: 0.0005 or negligible
Charge: -
Nucleus location
In the middle of the atom
Contents of nucleus
Protons
Neutrons
Charge of nucleus
Positive
due to the protons
Radius of nucleus
0.073nm
Electron location
Orbit around the nucleus in energy shells
RADIUS of an atom
10^ (-10) m
