Atomic Structure summary notes for AQA A level Chemistry

Atomic Structure

, Atomic Structure
Atoms are made up ofprotons, neutrons and electrons.
·The nucleus contains the protons and neutrons.
·
The electrons surround the nucleus.


Atomic number:number ofprotons
Mass number:number ofprotons + neutrons.


sotopes: Atoms with the same number of protons but different number of neutrons.
·

Isotopes of the same element react
chemically in
exactly the same
way
as
they have the same electron
configuration.
Electron Arrangement
Electron
and
transitioning:
to
John
other
discovered
shells
in
within
atoms
the
thatelectrons
atom.
can
gain energy
jump
-


or Example:Ground State
X
Eventually electrons return to
·




/
the first shell-which is back
to state.
- -




ground


electron transition an electron itcan
can
only have certain
·

n
the
a
energy e.g.
only have
energy of the shell thatits in. theres no inbetween. So
electrons
jump between
layers but
they cannot have the
energy from inbetween

layers.
Convergance limituntil
Electron shells are
converging convergance limitionisation they can no

longer converge.

Converge: Shells getting closer
together
·




If an electron excedes the
convergence limit. the atom molecule becomes ionised.

The shells are
converging