What’s the matter?
Please complete the handout IS IT MATTER.
• In your explanation, please include the
Your claim(answer that expresses the answer
to the question)
• Your evidence (information that supports the
• Your reasoning (the justification that links the
evidence to the claim)
Write in complete sentences.
Please determine on your post-it whether
these items are matter or not! (2 minutes)
Paper Air Thoughts Light Heat
Helium Apples Gravity Cells
Stars Fire Desk Cookies
Items on the list considered to be matter
are rocks, baby powder, milk, air, dust,
cells, atoms, smoke, salt, Mars, Jupiter,
steam, rotten apples, water, bacteria,
oxygen, stars, and dissolved sugar.
• Fire may be considered matter or
energy—the vaporized gases in the flame
are matter but the light and heat emitted
Students will examine the
scientific view of the nature of
• a. Distinguish between atoms and
• b. Describe the difference between
pure substances (elements and
compounds) and mixtures.
matter is made up of particles (e.g.,
atoms or molecules); has mass; takes
up space (has volume); and exists in
the forms of solid, liquid, gas, or
plasma. In order to be considered
matter, an object, material, or
substance must meet these
is the amount of
space an object occupies or
To measure liquid volume, use
a graduated cylinder. Unit:
of a regularly
v= l x w x h
Unit: m3 or cm3
of an irregularly
shaped solid object
• Measure the volume of
water that the object
• Unit: cm3 (cubic
Matter is made of particles called atoms and
An atom is the smallest part of an element
that can be identified as that element. Or
Tiny particles that make up elements.
Elements are simple substances that cannot
be broken down into any other substances
by chemical or physical means.
comes from a Greek term
meaning indivisible (cannot be
divided). (By modern definition,
atoms are not indivisible
because they are composed of
•Just How Small are Atoms?
could fit end to end across the
period at the end of this sentence and
the number in a single drop of water
(1022 to 1023 atoms) may exceed the
number of stars in the observable
•Yet, atoms are composed of
Central Core of the atom
Contains protons and neutrons
Protons have positive electrical
Neutrons carry no electrical charge
and are considered NEUTRAL (get
How much to enter this nucleus?
For you, no charge
(Sorry – it will happen again!)
in all directions around the nucleus
• Carry a negative electrical charge
• Not all the same distance away from the
NUMBER: the number of protons
in the nucleus of an atom.
Atomic Mass – Atomic Number = Number of Neutrons
Number of Protons = Number of Electrons
Farthest away from the nucleus and are
involved in bonding
• Electron Dot Diagram: Way to show the # of
Gain or loss of electrons is called ionization
lose an electron; atom becomes
gain an electron; atom becomes
•The arrangement of the electrons
atomic orbital and the electrons
in it are associated with a specific
amount of energy.
•The farther an electron
is from the nucleus the
greater its energy.
location of the orbiting electrons
will hold only set amounts of electrons
1st shell = 2
2nd shell = 8
3rd shell = 18
4th shell = 32
5th shell = 50
6th shell = 72
2(N2) = number of electrons in shell
2(12) = 2
2(22) = 8
2(32) = 18
2(42) = 32
Similarly charged particles repel
The positively charged protons in
the nucleus and the negatively
charged electrons is what holds
the atom together.
•Building an Atom
Electrons by themselves
would be poor building
blocks because like
charges repel, and they
would just repel each
• Protons have the same problem. They
repel each other and would build
• But electrons are attracted to protons.
atoms have identical numbers of
electrons and protons making them
electrically neutral overall.
Atoms with the same number of protons
but a different number of neutrons.
• Example: an atom with one proton, one
electron and one neutron is hydrogen.
• However, if the hydrogen atoms has two
particles (neutrons) but the same number
of protons (in the case of hydrogen one) it
is an isotope of hydrogen.
Thomson Model, 1904
- “plum pudding” model
- does not distinguish a nucleus or
electron orbits (shells)
Rutherford Model, 1911
- nucleus with orbital rings
Bohr Model, 1913
- nucleus with rings around it
– easy to use and understand
Lewis Structure, 1916
- chemical symbol surrounded with
dots representing valence electrons
(rather than rings)
used in chemical formulas to represent
behavior of atoms
electron cloud Model, 1920’s
- based on x-ray technology
began with Democritus; 400’s BC
-thought that everything was made up
of a few simple parts he called atoms
John Dalton started the Atomic Theory
-based on experimental support
-all matter is made of atoms
-chemical reactions are rearrangements of
scientists can still only see the electron
cloud even with the best technology
it takes about a million atoms lined up in a row
equal the thickness of a human hair
theory continues to change based on the
and behaviors of substances during tests
of two or more atoms joined in
a definite ratio.
• Most are composed of atoms of two or
• An element is a substance that cannot
be broken down into any other
substances by chemical or physical
molecule consists of two or more
atoms of the same element, or different
elements, that are chemically bound
• Diatomic molecules are made of two
atoms of the same element.
• Oxygen – O2
• In the animation above, two nitrogen atoms
(N + N = N2) make one Nitrogen molecule .
When atoms share one or more pairs of
Example: Oxygen shares one of its
electrons with each of the two hydrogen
Oxygen’s outer shell is now filled with 8
Each hydrogen atom share its 1 electron
with the oxygen atoms so they now have
2 electrons in their outer level.