Introduction to Chemistry
v Matter
is anything that occupies space and has mass.
Everything you can touch is made of matter. If it is made of anything, that anything is matter. Everything you will learn about Chemistry will all be based on how matter reacts and combines.
v Matter
has many properties. It can have PHYSICAL properties like different densities,
melting points, boiling points, freezing points, color or smells.
v There
are also CHEMICAL properties that define matter. A good example of chemical
properties is the way elements combine with each other in reactions.
The
big thing to remember... Matter can change in two major ways, physically and
chemically.
v All
matter is made of small particles called atoms.
Atoms
are too small to be seen with the unaided eye or even the microscope. In fact, more than a trillion atoms could fit over
the period of a sentence!
v Matter
that is made up of all one kind of atom is called an element.
An
element is a substance that cannot be broken down by chemical processes into simpler
substances.
v A
compound is two or more elements linked together chemically.
For example, when one
atom of sodium (which by itself is a soft metal) and one atom of chlorine (which by itself
is a poison green gas) combine, the result is a compound called sodium chloride, more
commonly known as table salt.
v Atoms are made up of: protons, neutrons, and electrons.
v Protons are particles with a relatively
large mass and a positive charge.
v Neutrons are particles with about the same
mass as protons and no charge.
v Electrons are particles with a relatively
small mass and a negative charge.