Introduction 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.

• 96% 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 (matter) that retains all the properties of that element

• Atoms are made of three parts.

The Nucleus

• The NUCLEUSConsists of 2 parts

• positive charged

protons• neutral neutrons

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

• Elements combine with other elements in a predictable fashion

Carbon

Oxygen

Hydrogen

Compounds

• A compound is a pure substance made up of atoms of two or more different elements

– The ratio of atoms are always fixed for a particular compound.

H2O

Chemical formulas shows the kinds and ratio of atoms of each element that occurs in a particular compound.

Water = 2 Hydrogen + 1 Oxygen

Simplest form of a substances of two or more atoms held together• (a compound such as water held

together by covalent bonds)

that retains all of the properties of the substance

Some molecules are large and complex. These are not large

Molecules

Large Molecules in Organisms

Nucleic Acids

Macromolecules