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Physics revised paper 1 (part 2) - Coggle Diagram
Physics revised paper 1 (part 2)
Atomic Structure and the Periodic Table
Atom basics
Tiny
Greeks believed the 'atomos' was the smallest thing in the world
So much so that 'atomos' meant 'uncuttable'
Made of 3 particles
Proton
Protons have a mass of 1
And a charge of +1
Neutron
Neutron has a mass of 1
And a charge of 0
Electron
Electrons have a mass of 1/2000 or 0.005
And a charge of -1
Atoms are infinitesimally small particles which make up everything in the universe
Compounds
Compounds are 2 or more elements that are bonded together
Periodic Table
The Periodic Table is a Graph that shows all 118 discovered 'elements' (types of atoms) in the world
Structure of the atom
The atom is made up of 2 parts
The Nucleus
The Nucleus is made up of protons and neutrons
and the shell
The shell is made up of electrons
Elements on the periodic table
The boxes containing elements on the periodic table have 4 parts
Symbol
Self explanatory, just avoid mishaps with symbols being different to names ( Potassium symbol= K)
Name
Self explanatory
The atomic number
Atomic Number = Protons = Electrons
Atomic number < Mass number
Mass number
Mass number= Protons + Neutrons
Mass number > Atomic Number
Energy of Molecules in a System
Graph
Info on the graph
Dotted arch is low temperature
Solid arch is high temperature
X axis is the Energy (in Joules)
Y axis is the numberr of molecules
Dotted line is when molecules have enough energy to evaporate
Isotopes
Definition
An isotopes is an atom with the original amount of protons and neutrons as a regular atom of that element but has more/less electrons
In short a different mass number, same atomic number
Rules
Metals can only lose electrons, giving them a + charge
Non-metals can only gain electrons, giving them a - charge
What group you are in shows how many electrons you lose, e.g. Berylium (A solid in Group 2) loses 2 electrons
With Non-Metals, Group 7 Chlorine doesn't gain 7 electrons, it gains 1. Group 6 Oxygen gains 2, Group 5 Nitrogen gains 3 etc.
History of the Atom
Ancient Greece (700BC-146BC)
Believed in 5 types of matter
Fire
Hot and Dry
Water
Cold and Wet
Earth
Cold and Dry
Air
Hot and Wet
Aether
Heavenly substance
Also created the word 'atomos'
Which means uncuttable
John Dalton (1860s)
Discovered the fact that atoms are tiny, solid spheres
J.J Thomson (1897)
Discovered the theory of the Plum Pudding Model
Tiny positive 'pudding' embedded with negative 'plums'
Lord Ernest Rutherford (1909)
Did the infamous 'Rutherford Experiment' (See separate branch)
Through this, he discovered the Proton
And through that, discovered the electron
Niels Bohr (1913)
He discovered that electrons don't float aimlessly round the proton 'nucleus', they orbit in 'shells'
James Chadwick (1932)
Discovered the 'Neutron'
A neutron is a neutrally charged particle that belongs in the nucleus, along with the protons and other neutrons
Plum Pudding Model and Rutherford's Experiment
Basis of the Plum Pudding Model
The plum pudding model is made up of two main parts
A 'pudding' of positive matter
Several negative 'plums' that are embedded in the positive matter
Rutherford's Experiment
The process
Rutherford and his student, Marsden, set up an 'alpha particle gun' to be fired at a thin sheet of gold foil
Their expectations were that all the strong alpha particles would go through the thin sheet
Result
They were partly correct in their predictions, with most going through, but some bounced off, which in today's circumstances, is like seeing a bullet bounce off a sheet of paper
Types of Radiation
Beta Radiation
What is it?
An electron
Atomic Makeup
1 electron
Rewritten as...
ß, 0, -1. ß is the symbol, 0 is the mass and -1 is the charge
Size
Average
How ionising?
Relatively ionising
What is needed to stop it?
Foil
How penetrating?
Relatively penetrating
Gamma Radiation
What is it?
An Electromagnetic Wave
Atomic makeup
Doesn't really have one, it's an electromagnetic wave
Rewritten as...
y, just y, as it's not atomic
Size
Small
How ionising?
Not very ionising?
What is needed to stop it?
Lead
How penetrating?
Very penetrating
Alpha Radiation
What is it?
It is known as a Helium nuclei
Atomic Makeup
2 Protons, 2 Neutrons
Rewritten as...
a, 4, 2. a is the symbol (slightly different a though, the alpha symbol), 4 Mass, +2 Charge
Size
Large
How ionising?
Very Ionising
How penetrating?
Not very penetrating
What is needed to stop it?
Paper, something thin
Other notes
You measure radiation with a 'Geiger-Muller Tube' which clicks every time it detects radiation
The Unit of measurement for radiation is 'Becquerels (B)
Half-Life
Definition
The time it takes for the radioactivity to 1/2 in number of atoms
General facts
The half-life can be between milliseconds and years
Francium has the shortest half-life of 22 minutes
Xenon-124 has the longest recorded half life at 18 sextillion years
Different Isotopes have different half-lifes
Decay
Alpha Decay
For example take Uranium. Uranium has a mass number and an atomic number of 92. An alpha particle has a 4 mass number and a 2 atomic number, so you subtract the atomic numbers, giving you 90, or the element of Thorium
Beta Decay
Beta Decay has a mass number of 0 and an atomic number of -1, so if you take Uranium and do 92--1 it would equal 93, or Neptunium
Please note that the Mass number being different is fine, it just means it's an isotope
