Atoms and Molecules: Basics and Models
Matter is anything that occupies space.
All matter is made of atoms.
Atoms are the building blocks of matter.
This model of the
atom may look
familiar to you. This
is the Bohr model.
In this model, the
nucleus is orbited
by electrons, which
are in different
energy levels.
A model uses
familiar ideas to
explain
unfamiliar facts
observed in
nature.
A model can
be changed as
new
information is
collected.
In 1908, the English
physicist Ernest
Rutherford began to
unravel the mysteries
of the
atomic
structure.
Through his
experiments he
discovered that atoms
were mostly
open
space
.
Rutherford
concluded that an
atom had a
small,
dense, positively
charged center.
He called the
center of the atom
the “
nucleus
”
The nucleus is
tiny
compared to the
atom as a whole.
In 1913, the
Danish scientist
Niels Bohr
proposed an
improvement. In
his model, he
placed each
electron in a
specific
energy
level.
According to
Bohr’s atomic
model, electrons
move in definite
orbits
around the
nucleus, much like
planets circle the
sun. These orbits,
or energy
levels
,
are located at
certain distances
from the nucleus.
According to the
modern atomic
model, an atom
has a
small
positively charged
nucleus
surrounded
by a large region in
which there are
enough electrons
to make an atom
neutral.
A space in which
electrons are likely
to be found.
Electrons
whirl
about the nucleus
billions of times in
one second
They are not
moving around in
random
patterns.
Location of
electrons depends
upon how much
energy
the
electron has.
Depending on their
energy they are
locked into a
certain area in the
cloud.
Electrons with the
lowest
energy are
found in the energy
level
closest
to the
nucleus
Electrons with the
highest
energy are
found in the
outermost
energy
levels, farther from
the nucleus.
The
Atomic -
Molecular Theory of
Matter
states that
all matter is
composed of small,
fast moving
particles called
atoms. These
atoms can join
together to form
molecules.
Nucleus
- the
central portion of
the atom.
Contains the
protons and
neutrons.
Electron Cloud
- area around the
nucleus where electrons are found.
Electrons are arranged within the
electron cloud in energy levels.
(Energy levels are sometimes called
shells or orbits).
è
Proton
- positive
charged particle
found in the
nucleus.
è
Neutron
- particle
with no
charge. Found in
the nucleus.
è
Electron
- negative
charged particle
found within the
electron cloud
In an atom, valance
electrons can be
found in the
outermost electron
shell. They are the
main point of
interaction between
one atom and
another, and are
very important for
the formation of
molecules.
A
molecule
is the
smallest particle of
a pure chemical
substance that still
retains its
composition and
properties.
Molecules
are
made of two or
more atoms.
Explore the world of atoms and molecules with a focus on distinguishing between them, understanding atomic structures through historic models like Bohr and Rutherford, and the modern atomic model. Discover how atoms form the basis of all matter and how they are organized within molecules.
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Presentation Transcript
Atoms and Molecules S8P1.a. Distinguish between atoms and molecules.
Matter Matter is anything that occupies space. All matter is made of atoms. Atoms are the building blocks of matter.
Atoms, Molecules and Elements
Atomic Models This model of the atom may look familiar to you. This is the Bohr model. In this model, the nucleus is orbited by electrons, which are in different energy levels.
Atomic Models A model uses familiar ideas to explain unfamiliar facts observed in nature. A model can be changed as new information is collected.
Ernest Rutherford In 1908, the English physicist Ernest Rutherford began to unravel the mysteries of the atomic structure. Through his experiments he discovered that atoms were mostly open space.
Ernest Rutherford Rutherford concluded that an atom had a small, dense, positively charged center. He called the center of the atom the nucleus The nucleus is tiny compared to the atom as a whole.
Bohr Model In 1913, the Danish scientist Niels Bohr proposed an improvement. In his model, he placed each electron in a specific energy level.
Bohr Model According to Bohr s atomic model, electrons move in definite orbits around the nucleus, much like planets circle the sun. These orbits, or energy levels, are located at certain distances from the nucleus.
Todays Atomic Model According to the modern atomic model, an atom has a small positively charged nucleus surrounded by a large region in which there are enough electrons to make an atom neutral.
Electron Cloud A space in which electrons are likely to be found. Electrons whirl about the nucleus billions of times in one second They are not moving around in random patterns. Location of electrons depends upon how much energy the electron has.
Electron Cloud Depending on their energy they are locked into a certain area in the cloud. Electrons with the lowest energy are found in the energy level closest to the nucleus Electrons with the highest energy are found in the outermost energy levels, farther from the nucleus.
Atomic - Molecular Theory of Matter The Atomic - Molecular Theory of Matter states that all matter is composed of small, fast moving particles called atoms. These atoms can join together to form molecules.
Atomic Structure Nucleus - the central portion of the atom. Contains the protons and neutrons.
Electron Cloud - area around the nucleus where electrons are found. Electrons are arranged within the electron cloud in energy levels. (Energy levels are sometimes called shells or orbits). Atomic Structure
Subatomic Particles Proton - positive charged particle found in the nucleus. Neutron - particle with no charge. Found in the nucleus. Electron - negative charged particle found within the electron cloud
Valence Electrons In an atom, valance electrons can be found in the outermost electron shell. They are the main point of interaction between one atom and another, and are very important for the formation of molecules.
Molecules A molecule is the smallest particle of a pure chemical substance that still retains its composition and properties. Molecules are made of two or more atoms.
Making molecules with atoms
