C1 - Particles Flashcards
Describe the particles in the three states of matter.
Solid - Strong forces. Particles vibrate around a fixed point, arranged in a regular lattice, no free space between particles. Fixed position and volume.
Liquids - Some force between particles. Irregular arrangement of particles. No definite shape but keep the same volume. Energy increases with temperature and can move faster.
Gasses - No force between particles, move freely. No fixed shape or volume but will always fill a container.
List some disadvantages of the particle model.
Particles aren’t spheres
They’re not solid.
Model also does not give any idea of size or space between them.
What kind of change is a change in the state of matter?
Are they reversible?
Physical change
Yes, they are reversible (Unlike Chemical Changes which are hard to reverse)
What did John Dalton say about atoms in the 19th Century?
Solid spheres - exist in everything.
Describe the Plum Pudding model and who made it.
1897- JJ Thompson
Atoms must contain smaller negatively charged particles (electrons).
Plum pudding; large, positively charged ‘pudding’ with negatively charged electrons inside.
What was the Gold Foil Experiment and who was it conducted by?
Earnest Rutherford 1909
Fired positively charged alpha particles at a very thin sheet of gold foil. They expected them to pass through.
Some did, but some completely deflected back.
This meant the model could not be correct.
Came up with the atomic atom model - Had a positively charged nucleus surrounded by negative electrons.
What was Bohr’s atomic model?
Electrons can only exist in fixed orbits (shells). Each shell has a fixed energy.
What is Scientists ‘Peer review’
Other scientists can see new discoveries and comment/change ideas to check for errors and develop their work.
What three subatomic particles make up an atom?
What are their charges?
. .Relative Mass. Relative Charge
Protons. 1. +1
Neutrons 1 0
Electrons 0.0005 -1
Describe the nucleus of an atom.
1) The nucleus is in the middle of the atom.
2) It contains protons and neutrons.
3) It has a positive charge because of the protons
Describe the electrons in an atom.
1) Electrons move around the nucleus in electron shells (or orbitals).
2) They’re negatively charged.
3) They’re tiny, but their orbitals cover a lot of space.
What is a molecule?
Chemical made of two or more atoms (can be the same atom)
What does the (a. Mass number) & (b. Atomic Number) tell you about an atom?
Mass number = Total no. of protons and neutrons
Atomic Number = Number of protons. (and Number of electrons)
How do Ions form?
How are positive and negatives form?
When an atom gains or loses electrons.
Positive - when electrons are lost
Negative - when electrons are gained
Revise Image C1.1
What is an isotope?
Same number of protons, different number of neutrons.
