atom- the Greek word for atomos.
 Atoms are incredibly small placed side
by side.
 The subatomic particles make up atoms
are protons, neutrons, and electrons.
 The electron is a negatively charged
particle.
 Atoms have equal numbers of electrons
and protons.

A chemical element is pure substance.
 C for carbon, H for hydrogen, Na for
sodium.
 The sum of protons and neutrons in the
nucleus is called mass number.
 Some isotopes are radioactive.
 A chemical compound is a substance
formed by the chemical.

An ionic bond is formed when one or
more electrons are transferred.
 An atom gains electrons.
 In a salt crystal
 The attraction between oppositely
charged ions is an ionic bond.
 Covalent bond forms when electrons are
shared.
 Molecule is smallest unit of compounds.

A water molecule is neutral.
 An oxygen atom has much stronger
attraction for electrons.
 The oxygen atom is on one end of the
molecule and the hydrogen atoms are
on the other.
 Water molecule is polar.

The charges on a polar molecule are
written in parentheses.
 cohesion is an attraction between
molecules of different substances.
 Waters cohesion causes molecules.
 Cohesion holds the column of water
together as it rises.

Water is not always pure. Water is often
found as part of mixture.
 Water is the solvent
 Table salt is the solute
 The ions gradually become dispered in
the water .

Carbon can bond with many elements.
 Carbon atom can bond to other carbon
atoms.
 Monomers join together to form
polymers.
 Living things use carbohydrates as their
main source of energy.
 Plants use starch.

A chemical reaction is a process that
changes one set of chemicals into
another set of chemicals.
 Chemical reactions involve breaking of
bonds in reactants and formation of new
bonds.
 When hydrogen gas is ignited the
reaction is rapid.
 An example of chemical reaction is in
your body.

Energy is released or absorbed.
 Energy is released in form of heat.
 Organisms carry out reactions.
 Energy changes are important.
 Plants get their energy from trapping
and storing energy from sun.
 Energy is released in the form of heat.

Large
 Steroids are lipids.
 Fats, oils, and waxes.
 Used to store energy.
 Carbon and hydrogen atoms.
 Steroids serve as chemical messengers.

Macromolecules.
 Nitrogen base
 Amino acids
 Dna contains the sugar deoxyribose
 Two types of nucleic acids

Macromolecules
 Contains nitrogen
 Carbon
 Oxygen
 Polymers of molecules
 More than 20 diff. amino acids
 Amino group
