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