Atoms and Molecules – Today’s Science Word

Would you believe it if I told you that you and I, the ground we walk on, the sun, and everything else is made of the same things?  We are all composed of atoms.  Atoms are the smallest thing that exists that gives a substance its chemical properties.  Atoms are made of two main parts.

The NUCLEUS of the atom holds almost all of its mass.  This is where positively charged protons and uncharged neutrons sit.  Neutrons and protons actually have about the same mass.

ELECTRONS orbit the nucleus in a cloud, sitting at specific distances or ORBITALS around the nucleus.  Being negatively charged, electrons are constantly being repelled by the positively charged nucleus, but are being pulled into their orbit by gravity.  Also, it’s interesting to know that electrons are extremely low mass.  Protons are 2000 times larger than electrons!

If you’ve ever seen the periodic table, you know that it lists ELEMENTS.  A single unit of an element is one atom of that element, and the only thing that makes one element different from another is the number of protons.

Now what do you call a bunch of atoms put together?  You may have already guessed that this is a MOLECULE.  Every chemical compound has a recipe that makes it up, and the smallest unit of that recipe is the molecule.

For example, let’s look at a water molecule.  Every water molecule is made up of 2 hydrogen atoms and 1 oxygen atom.  For short, we call water H2O.  Every chemical compound has its own recipe that describes the molecule that makes it up.

NaCl is sodium chloride, also known as table salt.

What about H2O2?  It may look like it’s similar to water, but that slight change makes it hydrogen peroxide, which is not safe to drink at all!