Topic 1 Flashcards
John Daltons Atomic theory 1803
Matter is made of atoms which are tiny particles which cannot be created, destroyed or divided
Atoms of the same element are identical, and atoms of different elements different
Different atoms combine together to create new substances
Who discovered the electron
JJ Thompson
Discovery of the electron
JJ Thompson discovered the electron by using a cathode ray tube which identified th electron as a negatively charged particle hence proving that atoms are divisible
Thompsons model after discovering electron
Plum pudding model : negative electrons spread through positively charged material
Who discovered the nucleus
Ernest Rutherford
The discovery of the nucleus
Gold foil experiment
Rutherford shot a beam of positively charged particles at a thin sheet of gold foil and based on the plum pudding model expected the particles to pass through the foil because the positive charge of the nucleus was thought to be evenly spread out
Some particles scattered however and a few were deflected directly back which led to the idea that most of the atoms mass is centred in the nucleus
The Bohr model
Niels Bohr further develop Rutherford concept and suggested that electrons orbit in shells
This model showed why the nucleus does not collapse inwards
Proton relative mass
1
Neutron relative mass
1
Electron relative mass
1/1840
Proton charge
+1
Neutron charge
0
Electron charge
-1
Atomic number
The number of protons in the nucleus of the atom
Mass number
The sum of the number of protons and neutrons in an atom
Relative atomic mass calculations
(%of isotope a x mass of isotope a) + (% of isotope b x mass of isotope b) / 100
Mendeleev arrangement
Verticle columns based of their properties of their compounds and arranged them horizontally in order of increasing atomic mass
How is the table arranged in modern day
Increasing Atomic number
Each element has one proton more than the element preceding it
In metals The further down a group and element is
The more easily it can react and lose its outer electron
This is because the atomic size is larger so the shells are further away from the nucleus
Weakening their attraction
In non - metals the higher up the period the more reactive it is
This is because it is easier for them to gain an electron than lose one as they have fuller outer shells
Ions
Electricity charged particles formed by the loss or gain of electrons
Negative ions are called
Anions and from when electrons are gained
All metals become
Cations
All non metals become
Anions
Ionic bonds
Strong electrostatic forces of attraction between oppositely charged ions
Ionic lattices
A regular repeating arrangement of ions
High melting and boiling points due to strong electrostatic forces of attraction between oppositely charged ions
Ions with a higher charge have
Stronger forces of attraction so higher melting and boiling points
IDE ending means
Non metal element
Ate ending
Oxygen is present
Clhoride charge
Cl-
Bromide charge
Br -
Iodide charge
I-
Nitrate charge
N03 -
Sulfate charge
S04. 2-
Carbonate
C03 2-
Covalent bonding
A shared paint of electrons between atoms
Covalent bonds between atoms are
Strong
Simple covalent bonds do not conduct electricity as
They do not contain free electrons
Empirical formula
Dividing the reacting masses by the relative atomic mass of each element (moles)
Divide each result by the lowest number obtained to give the simplest ratio
Concentration equation
Mass of solute in grams / volume in dm3
Formula triangle for moles
Particles
Moles x avogadros constant
Converting between moles triangle
Mass
Moles x mole mass