Save
Chemistry paper 1
Atomic Structure and Periodic Table
Atoms
Save
Share
Learn
Content
Leaderboard
Learn
Created by
Ciaran McKenna
Visit profile
Cards (5)
all
substances
are made of
atoms.
They're extremely
small
and can't be seen without a
microscope.
They have a radius of
0.1 nanometres
Nucleus:
in the
middle
of the
atom
contains
protons
and
neutrons
positive
charge
almost the
whole
mass
of the atom is in the
nucleus
Electrons:
move
around
the
nucleus
in
electron shells
negatively
charged and
very
small
cover a
lot
of
space
has virtually
zero mass
Number of protons equals number of electrons:
Atoms are
neutral-
they have
no charge overall
This is because they have the
same number
of
protons
and
electrons
The
charge
on the
electrons
is the
same size
as the
charge
on the
protons
but
opposite
so charges
cancel out
Atomic number and mass number describe an atom:
The
nuclear
symbol of an atom tells you its
atomic
(
proton
) number and
mass
number
The
atomic
number tells you how many
protons
there are
The
mass
number tells you the
total
number
of
protons
and
neutrons
in the atom
To get the number of
neutrons
, just
subtract
the
atomic
number from the
mass
number