These revision notes for Edexcel A-Level Chemistry Unit 1 cover atomic structure and the periodic table in detail. Key topics include the properties and significance of subatomic particles, the principles of electron configuration, and the trends observed across the periodic table. Additionally, th...
Chapter 1 - Atomic structure and the periodic table
History of the atomic Structure
-
Democritus (460 to 370 BCE)
) miniscule
↳
and invisible Spheres that cannot be cut any smaller
-
John Dalton (1766-1844)
↳ All elements are made up of indivisible particles called atons
↳ All atoms of identical and have the some wall
a given element are
↳ The atons of different elements have different masses
are now
↳ They can combine to form molecules in compounds
4) All the molecules of a given compound are identical
Some of John Dalton's theories have been proven to be incorrect
4 Indivisible Particles >
-
atens can be broken down into Subatomic Particles
4) Isetopes mean not all atons in a given element are the same
2) Isotopes mean molecules or a givee compound are not identical
Discovery of inside atoms (1847-1932)
- J J
.
. Thomson (1836-1940)
4) cathode
ray experiment (the narrow rays were deflected using charsed plates
4 Introduced Charges to the atom
)
↳
Discovered the electron
↳ Plan pudding model (positively charged cloud with electrons in it
-
Ernest Rutherford (1871-1937)
↳ Gold toil
experiment
2 Shot Alpha foil
rebounded back
particles at gold
4 Some were deflected when all should have gone through
↳
Protons are discovered
- Nuclear model (how atous are most empty space with a nucleus
, James Chadwick (1891-1974)
-
)
↳
problem with Rutherford's model is that relative masses of certain elements
did not match up (Something within the atoms of elements were giving them
more mass)
↳ Bombarded
Beryllium with alpha particles
↳ found new radiction that has no electric charge
4) Discovered the neutron within the nucleus
Atomic properties of subatomic particles
Atomic number (2) -
The total number of protons within the aton of an element
↳ The atanic what
number decides element it is
4) Every element has a unique number of proton
Mass number (A) -
The total number of protons and neutrons within the nucleus
of an atom of an element
4 Masl number is not always the same with aton
every of an
element because of isotope
4 The mess of electrons are usually isnored because they
have negtiable wass
E "He'+X
12 16
6 8
I iH general formula
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