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Topic 4:
Atomic
Structure
ALL atoms are made up of
combinations of three basic ‘subatomic’ particles...
Protons
Electrons
Neutrons
PROTON
Charge: Positive (+)
Location: Nucleus
Size: Large (same as neutron)
Mass: 1 amu
ELECTRON
Charge: Negative (-)
Location: Orbiting the Nucleus
Size: Small (about 1/2000th the size of
protons or neutrons)
Mass: 0 amu (too small
to count)
NEUTRON
Charge: Neutral (o)
Location: Nucleus
Size: Large (same as proton)
Mass: 1 amu
Ode To A Proton
by Shay Heather Davies - 19th May 1998
Oh proton, how your positive charge makes me blush!
I watch you from a distance, and my heart turns to mush...
If only I was a neutron, we could frolic for awhile,
and then my dear I'm sure, I would wear a permanent smile.
But alas, I'm an electron, and I must watch you from afar,
so far from where you are...
It seems to me that my fate is sealed,
but how can my love not be revealed?
My mass won’t be complete until you’re mine,
so give me this chance, and show me a sign.
Some day we’ll meet and I'll see your eyes,
and we will be together and neutralize...
so until that day, farewell my opposite attract,
my love for you remains intact.
Important numbers for each
type of atom… each ‘element’:
Atomic mass - Atomic Number = # of neutrons
(total mass of
protons and
neutrons)
(total number
of protons)
Some atomic masses may be
written as a decimal (e.g. Carbon
is actually 12.01, not ‘12’)
This is because some elements
have atoms with varying
numbers of neutrons in the
nucleus.
We call these different atoms of
the same element ‘ISOTOPES’
Example #1 : Isotopes of Hydrogen
Atoms of elements always have equal numbers of protons
(positive charges) and electrons (negative charges).
The number of neutrons (which are neutral) an atom has can
vary.
NOTE: Tritium NOT Titrium
Example #2 : Isotopes of Carbon
Carbon-14 doesn’t
have a special name
as the isotopes of
hydrogen do. It is
the isotope of carbon
we use to ‘date’ how
old something is.
Note that the ‘% Today’
(usually written as ‘%
abundance’) is an
indication of the
fraction of ALL carbon
that is of that particular
isotope.