Intoduction to
CHEMISTRY
Composition of Matter
• Everything
in
Universe is composed
of matter
– Matter is anything
that occupies space
(has volume) and
has mass
Everything in Universe is
composed of matter.
• Matter is everything
around you.
• Matter is anything made
of
– atoms and
– molecules.
• 90% of the mass of
an organism is
composed of
• 4 elements (kinds of atoms)
• Oxygen
• Carbon
• Hydrogen
• Nitrogen
Each element (atom) is unique and arranged in the
“Periodic Table of the Elements” is a nicely
organized collection of data about the properties
of the elements.
Atoms
• Are the simplest
particle of an
element that retains
all the properties of
that element
• Atoms are made of
three parts.
The
• The
Nucleus
NUCLEUS
Consists of 2 parts
protons
neutrons
• positive charged
• neutral
and the
Electrons
• Negatively charged particles
• Travel at very high speeds at
various distances around the nucleus
Protons
Neutrons
Electrons
Compounds
• Most
elements do
not exist by
themselves
• They combine
with other
elements in a
predictable
fashion
Carbon
Oxygen
Hydrogen
• A compound is a pure
substance made up of
atoms of two or more
elements
– The ratio of atoms are
always fixed for a
particular compound.
Chemical formulas
shows the kinds and ratio of atoms of
each element that occurs in a
particular compound.
Water—2 Hydrogen, 1 Water
H2O
• Molecules are the
simplest part of a
substance (a compound
such as water) that
retains all of the
properties of the
substance
• Some molecules are
large and complex
these are not
these are
Type of Molecules in Organisms
Nucleic Acids