each element different? Why are atoms of the element iron different from
atoms of oxygen? It's quite simple. Why is a banana different than an apple?
Because of what it's made of. Each atom has a couple important parts.
The simple illustration above shows what an atom looks like. See the red
dot on the outside? That is called an electron. The electron simply orbits or circles
the atom, similar to a satellite circling the earth. We call it an electron because
it has properties associated with electricity (you know, those positives and negatives
on a battery). Well, electrons have what we call a negative charge(-).
Electrons are little things and just like the atom, we cannot see them.
And the elecrons are even smaller than the atom (since the electrons are but one part). Now, there
are only a few other parts of the atom to learn. In the center of the atom, we
can see a blue dot and a black dot. Well, the blue dot is a proton. This part
of the atom has a positive charge. Since the electron has a negative chatge and
the proton has a positive charge, they are opposites, and in simple terms, have
an attractive force for each other. The electron is constantly orbiting the
atom very quickly. So fast in fact, that I often wonder why it doens't just spin
off into the sunset. However, the attractive forces of the positive proton
hold the electron in its orbit. The other black dot is neutron. It has no charge,
but has weight, and gives a degree of mass to the atom. There you have it. you've
learned the important parts of the atom. All atoms are like this. The only difference
between iron and oxygen are the numbers or protons, electrons and neutrons. for example
helium only has 1 electron and 1 proton. But lead has 79 electrons ! Imagine all
those little electrons spinning at once at mindboggling speeds, and not even colliding !
Isotopes are merely a variation of an element. For example, we discussed
hydrogen and its parts: 1 electron and 1 proton. Well, most hydrogen is like
this, and each hydrogen atom has a particular weight because of the
weight of the proton and electron (although electrons are very light
in comparison to protons. Protons weigh over 1800 times more than
electrons). However, a small percentage of hydrogen atoms
in existence have 1 electron, 1 proton and an extra neutron. What does this mean?
Well, it's still hydrogen, but because of the extra neutron present, the atom
is much heavier now. This is an isotope: merely a variation of an atom, with
different numbers of neutrons. so, what happens if we use this heavier isotope of
hydren to make water. Remember, water is H2O (2 atoms of hydrogen,
and 1 atom of oxygen). If we use the heavier isotope of hydren, we can still
make H2O, but the resulting water molecule will now be heavier because
of the heavier hydrogen used. Remember, the heavier hydrogen has an extra neutron,
which makes it heavier than the normal hydrogen with no neutron. So, what are the
implications of making a water molecule with this isotope of hydrogen? When
we build water with "heavy" hydrogen, we get "heavy water". In other words, a heavier
water molecule. This has implications in nature, because weight and other
properties of a molecule change the way it reacts with other substances.
More importantly some isotopes of certain elements are unstable and break apart
over time. When they self-destruct, they release large amounts of energy. This
is what we call radioactivity, and of course can be dangerous. Uranium is an
element that breaks down. It has what we call a half life. In this time, half
of the atoms in the sample, decay, and release lots of energy. This energy can
pass through us easily, damaging our DNA, etc., and this is why it has the potential to
cause tumours, cancer, and general tissue damage. Imagine the time when man was not
aware of this, and handled pure uranium with his or her bare hands. We have learned alot
through history, unfortunately through the sacrifice of others.