Classifying Matter Notes
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Chemical—substance that used in a chemical process or that is formed by a chemical
process or it may also be any substance that is always made of the same thing
o Ex. Water is always H2O
Chemicals can be natural or synthetic
o Natural—CO2, H2O, gold, and sugar
o Synthetic—chemicals made in the laboratory
 Ex. Plastic, steel, bronze
Matter is anything that has mass and volume
Mass is the amount of matter in a substance
Volume is the amount of space the substance occupies
The main three states of matter—solid, liquid, and gas
o Solid has a definite shape and volume—table, chair
o Liquid has a definite volume but not shape—water, oil
o Gas doesn’t have a definite volume or shape—air
Element-simplest form of matter, it can not be broken down into simpler substances by
ordinary chemical means
o Changing an element to another element requires a lot of energy such as a nuclear
explosion
o There are about 109 elements discovered
all of the known elements are combined into natural elements and synthetic elements—93
are natural elements, synthetic elements—16 that scientists created
Mixture—when two or more substances combine but do not join together chemically—
the different parts keep their individual identities (properties)
o Ex. Cereal(mix of bran, fruit, milk, etc) and air (mix of gases)
Compound—when two or more elements combine chemically, individual substances join
and do not keep their original properties
o Ex table salt (NaCl—sodium chloride), sodium by itself is a metal that explodes
in water and chlorine is a poisonous gas—together you can eat it
o Have a definite composition---NaCl is always table salt
o Can be broken down into simpler substances by chemical means meaning NaCl
can be broken into Na and Cl
o Can be identified by their physical properties meaning how you observe it and
measure it
Mixtures and compounds can be natural or synthetic
o Minerals are examples of natural mixtures
o Stainless steel is an example of synthetic mixture
Molecule—smallest unit of a compound that has all the properties of the compound
o Ex smallest molecule of water would be H2O
Chemical formula—the makeup of a compound, uses chemical symbols and subscripts to
identify the number of atoms of each element in a molecule of a compound
o Ex. H and O are chemical symbols of hydrogen and oxygen, 2 is the subscript for
the number of hydrogen atoms needed to bond with oxygen to make water…this
is the formula for water H2O
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o When there is not a subscript for a symbol that means there is only 1 atom
present, you need one sodium and one chlorine to make salt the chemical formula
is NaCl
Atom—smallest unit of an element that has the properties of the element, also called the
building block of an matter
 Three types of atom particles: protons, neutrons, and electrons
o Proton—a particle with a positive charge (+)
o Neutron—a particle without a charge (neutral) ( )
o Electron—a particle with a negative charge (-)
 Protons and neutrons are found in the center of the atom called the
nucleus
 Electrons orbit the nucleus in a region called the electron cloud
 Electrons have different amounts of energy
 The closest electrons have less energy than electrons farther
from the nucleus
 Electrons on the same energy level have similar amounts of
energy
 Each energy level can hold a certain number of electrons
Energy Level
Max Number of Electrons
1
2
2
8
3
18
4
32
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Valence electrons are found in the outer shell of the atom
o To determine how atoms combine to make compounds is dependent upon
the number and arrangement of valence electrons
Chemical bonds—forces that hold atoms together
o Ionic bond-when a bond is formed by losing or gaining electrons
o Ion—atom that has gained or lost one or more electrons
 Losses electrons—atom becomes positive
 Gains electrons—atom becomes negative
 Form because opposite charges attract
To bond atoms need to have a total of eight electrons in their outer energy level
o Atoms with 1, 2, or 3 valence electrons normally give their electrons to
atoms of elements that have 7, 6, or 5 valence electrons
Covalent bonds—atoms share valence electrons
o Form between elements whose atoms have 4, 5, 6, or 7 valence electrons