chemistry

chemistry topic 1

john dalton

john dalton

3-way atom theory

-atoms can’t be destroyed or created

• Atoms of the same element are identical; those from different elements are not.

- atoms join with atoms to make new substances

jj thompson

he used cathode ray tube to conduct experiment which proved dalton wrong

it showed that there were smaller negative component in a atom

came up with plum pudding diagram

ernest rutherford

he shot a ray at gold foil

thought all would come out from the back but the experiment showed some rays went to the side or came back

came up with the idea that an atom has a centre known as nucleus with electron flying randomly around it

^{proton , charge: +1 mass: 1}

^{neutron, charge;0 mass 1}

^{electron charge:-1 mass:1/1836}

mass no. neutron +proton

atomic no. proton or electron

some isotopes can have mass that isn’t whole no. cause of the atom having different variation they just take the masses and make a mean

isotope :variation of same atom

the formula for average mass

((mass of isotope a * of isotope a )+ (mass of isotope a* of isotope b ))/100

atomic table is in order of increasing atomic number in rows called period

most elements are metal and are found at bottom of table

electronic configuration is in shells of 2.8.8 ie 2 in the first one then 8 in second one and 8 in third one

Which group a element is in tells you how many electron are in the last shell

the period tells you how many shells there will be

metals become cations while non-metals become anions

ie metal become poitively charged while non metal become negetively charged

MIXTURE

A combination of two or more substances that are not chemically bonded together, retaining their individual properties.

SIMPLE DISTILATION

A separation technique used to purify liquids by heating to create vapor and then cooling to condense back into liquid, effectively separating components based on differing boiling points.

fractional distilation

used to separate oil and other mixtures into their individual components by utilizing differences in boiling points. eg is hydrocarbons distilled at different temprature’s

RF value (Paper chromotogrophy)

distance moved by substance / distance moved by solvent

Acids produce H + ions in aqueous solutions

Ziyan

alkalis produces OH in aqueous solution

Ziyan

the more H* ions in solution the more acidic :. less ph

• ph decreases by one unit the h* concentration increases by factor of 10