How can matter be classified?

Matter is made up of a basic “ingredient” known as atom. Atoms are the smallest units of an
element that maintains the properties of that element. The substances you encounter every
day can be classified in three major classes: Elements, Compounds, and Mixtures. They are all
made up of atoms but the atoms are mixed in different ways in each one of them.

You can picture atoms as building blocks and you can organize them in this way. If you put
one or more atoms of the same kind together the result will be an element, but, if you put two
or more atoms of a different kind what you will get is a compound. When you mix elements
and compounds what you get is a mixture.

What are pure substances?

Elements and compounds are pure substances. A pure substance is a substance that has
definite physical and chemical properties. This happens because pure substances are the ones
made of one type of particle. Even so compounds are pure substances because even though its
not the same kind of atom it’s the same kind of molecule. A molecule is a combination of two
or more kinds of atoms that are chemically combined.

Pure substances cannot be formed or broken down by physical changes. When a pure
substance undergoes a chemical change its no longer that same substance. Individual atoms
cannot be broken down by any normal physical or chemical change.

How can elements be classified?

There are over 100 elements but based on its physical and chemical properties we can
know to which category an element belongs to, by knowing this we can infer some of its
characteristics. They can be classified as metal, non metal, and metalloids. Metals tend to be
shiny, be good heat and electricity conductors and be molded into sheets or wires, non metals
are not shiny and they do not conduct heat or electricity well. Metalloids have characteristics
from both metal and non metal elements.

How can compounds be classified?

Compounds are classified by their pH into three different kinds: Neutrals, Bases and Acids.
Acids have a pH below 7, bases have a pH greater than 7 and neutrals have a pH of 7. They
can also be classified into organic and inorganic. Organic compounds are the ones who
contain carbon or hydrogen whereas inorganic ones don’t. compounds are also classified by
their role in the body. There are categories: lipids, carbohydrates, nucleic acids and proteins
Carbohydrates are used as a source of energy, lipids store excess energy in the body, protein
regulate chemical activities in the body and nucleic acids contain genetic information.

What are mixtures?

A mixture is a combination of two or more substances that are combined physically but
not chemically. Unlike elements and compounds a mixture is not a pure substance. Mixture
contain more than one substance but those substances have the same chemical make-up
they had before being mixed together. Mixtures can be separated by physical changes easily

because they are not combined chemically.

How can mixtures be classified?

There are two ways to classify mixtures, one is by the way they look. If we classify them this
way there are 2 kinds of mixtures the heterogeneous and the homogeneous. Homogeneous
mixtures are the ones in which substances are evenly spread and Heterogeneous one are the
ones in which you can spot its different substances.

But there is another way you can look at mixtures you can see them as suspensions, colloids,
and solutions. In a suspension particles are spread in a liquid or a gas but are too large to stay
mixed without being stirred. In solutions one substance is dissolved in another. And in colloids
it’s like both of them, the particles do settle but they settle really slow.

-Claudio