C1.Chemistry
Atoms
Smallest unit of matter
Elements - contain one type of atom
Compound - contains two or more elements chemically bonded together
Mixture - contains two or more elements not chemically bonded together
Contains the nucleus which has protons and neutrons in the centre surrounded by electrons orbiting the nucleus
Seperating Substances
Distilation
Seperating substances where the boiling points are very far apart - heat at a particular boiling point then one of the substances will travel up the condenser and condense and be collected as seperate mixture. Do this again with greater boiling points to condense of the other substances.
Fractional Distilation
Same as simple however the only difference is that they seperate substances that have close boiling points
Crystalisation
When you mix a solute into a solvent until its in excess and heat with a bunsen burner to form crystals. This is used with insoluble substances in a solvent.
Evaporation
Heating a solution which has a dissolved substance in it to the point of the solvents boiling point so that you are left with the dissolved substance
History of the Atom
Democritus - stated atoms are smallest possible unit of matter
John Dalton 1800s - Proposed that there was an atom for each representive element
JJ Thompson - Plum pudding model
Ernest Rutherford - Alpha Particle experiment discredited the plum pudding model
Niels Bohr - Nuclear model of the atom, shells contain electrons
James Simpson - Discovered a neutral charge atom and named it Neutron.
Metals
Metals are usually sonorous, malleable and good conductors of heat and electricity
They also have a high melting and boiling point which means they are hard at room temp
Normally form positive ions so lose electrons
Non metals
Gas or liquid at room temperature
Negative ions - gain electrons
Have the opposite chemical properties of metals
Found on the right side of the periodic table
Group 1 - soft, reactive forms 1+ ions. Reactivity increases as you go down the group.
Transition metals - form multiple ions as well as being able to be used as catalysts
Noble Gases - Inert as they have full outer shell no need to gain/lose electrons
Halogens - 7 electrons in their outershell reactivity decreases as you go down the group as does MP/BP. Fairly reactive group forms 1- ions.
Isotopes - variations of elements with the same number of protons but a different number of neutrons
Atomic number - number of protons in an atom of that element
Mass number - number of protons and neutrons of an atom of that element