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Atomic structure & the periodic table - Coggle Diagram
Atomic structure & the periodic table
atomic
Relative electrical charges
all atoms in a particular element have the same no. protons
atoms of different elements have different numbers of protons
the no. of protons in an atom is the atomic number
Proton:
+1
Atoms have no overall charge
Neutron:
0
Electron:
-1
In an atom, the no. electrons is the same as the no. protons in the nucleus
Size & mass of atoms
Neutron:
1
Electron:
1/200
Proton:
1
sum of the protons and neutrons is the mass no.
The nucleus has a radius of
1 x 10^-14
Atoms of the same element can have a different no. neutrons
(isotopes)
Atoms have a radius of about
1 x 10^-10 m
Development of structure of the atom
J.J Thompson (1897):
discovered electrons // plum pudding model // electrons stuck to outside of a solid sphere // used particle accelerate
Ernest Rutherford (1911):
GOLD FOIL EXPERIMENT
: projected a beam of particles at a thin sheet of gold to probe inner structure of the atom // some rebounded & came back // most of an atom is empty space w/ dense positive core
John Dalton (1802):
atoms are small & indivisible // all elements were made with different atoms
Niels Bohr (1913):
proposed the atom was like a tiny solar system // electrons orbit the positive nucleus
Democritus (400BC):
"If I cut an item in half is there a point where you can't cut it in half anymore // atoms are the smallest particles
James Chadwick (1932):
concluded there was the existance of zero charge neutrons // atomic mass of elements was often double it should be
Relative atomic mass
Mixtures
the chemical properties of each substance in the mixture are unchanged
separation techniques
simple distillation
heat up a solution, substance with lower bpt will evaporate go through condensing tube & into a different vessel
eg. to purify a liquid
Fractional distillation
the process of separating crude oil into hydrocarbons with similar numbers of carbon atoms
eg. crude oil
crystallisation
the process of forming crystals from a solution by allowing the solvent to evaporate
eg. getting salt from sea water
chromatography
separation of a mixture into its components, the mixture is dissolved in a fluid
eg. at a crime scene, painting, art work
filtration
used to separate an insoluble solid from a liquid
eg. separating sand from water or excess reactant from a solution
contains two or more elements or compounds not chemically bonded
Electronic structure
Atoms, elements & compounds
elements
Elements are shown in the periodic table
There are over 100 elements
Elements contain only one type of atom
compounds
Compounds contain two or more different elements chemically combined
They can be represented with formulae of the elements they were formed with
Chemical reactions always involve to formation of one or more new substances
(and often a detectable energy change)
Compounds can only be separated in chemical reactions
Compounds are formed from from elements in chemical reactions
atoms
atoms of each element are represented with symbols
(eg. Na is sodium)
atoms are made of protons, neutrons & electrons
Atoms are the smallest part of an element that can exist
atoms have zero overall charge
All substances are made of atoms
formulae is calculated by using the charge of the ion of the element -
(needs overall zero charge)
periodic table