Download Atoms

What’s the matter?
•Warm-up
Please complete the handout IS IT MATTER.
• In your explanation, please include the
following:
•
Your claim(answer that expresses the answer
to the question)
• Your evidence (information that supports the
claim)
• Your reasoning (the justification that links the
evidence to the claim)
Write in complete sentences.
•
•Warm-up
•
Please determine on your post-it whether
these items are matter or not! (2 minutes)
Paper Air Thoughts Light Heat
• Water
Helium Apples Gravity Cells
• Smoke
Stars Fire Desk Cookies
•
•Answer
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
are energy.
•
•GPS
• S8P1:
Students will examine the
scientific view of the nature of
matter.
Elements:
• a. Distinguish between atoms and
molecules.
• b. Describe the difference between
pure substances (elements and
compounds) and mixtures.
Matter is………..
• All
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
characteristics.
•Space
 Volume
is the amount of
space an object occupies or
takes up.
 To measure liquid volume, use
a graduated cylinder. Unit:
mL
• Volume
of a regularly
shaped object:
v= l x w x h
Unit: m3 or cm3
• Volume
of an irregularly
shaped solid object
• Measure the volume of
water that the object
displaces.
• Unit: cm3 (cubic
centimeters)
•Atoms



Matter is made of particles called atoms and
molecules.
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.
• Atom
comes from a Greek term
meaning indivisible (cannot be
divided). (By modern definition,
atoms are not indivisible
because they are composed of
smaller particles)
•Just How Small are Atoms?
• Millions
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
universe.
•Yet, atoms are composed of
smaller particles
Nucleus
 Central Core of the atom
 Contains protons and neutrons
 Protons have positive electrical
charge
 Neutrons carry no electrical charge
and are considered NEUTRAL (get
it???)

•Atomic Humor
• Neutron:
• Proton:
How much to enter this nucleus?
For you, no charge
(Sorry – it will happen again!)
•Electrons
• Travel
in all directions around the nucleus
• Carry a negative electrical charge
• Not all the same distance away from the
nucleus.
• ATOMIC
NUMBER: the number of protons
in the nucleus of an atom.
Atomic Mass – Atomic Number = Number of Neutrons
Number of Protons = Number of Electrons
•Let’s Practice
Atom
Hydrogen
Helium
Lithium
Beryllium
ATOMIC
SYMBOL
ATOMIC
NUMBER
NUMBER
OF
PROTONS
ATOMIC
MASS
NUMBER
OF
NEUTRONS
NUMBER
OF
ELECTRONS
•Valence Electrons
Farthest away from the nucleus and are
involved in bonding
• Electron Dot Diagram: Way to show the # of
valence electrons.
•
Gain or loss of electrons is called ionization
lose an electron; atom becomes
positive
gain an electron; atom becomes
negative
•The arrangement of the electrons
• Each
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.
•Atoms
Shells or
Energy Levels
location of the orbiting electrons
will hold only set amounts of electrons
1st shell = 2
2nd shell = 8
3rd shell = 18
Formula
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
2(52) =50
2(62) =72
•Electrical Charge
 Oppositely
charged particles
attract
 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
other.
• Protons have the same problem. They
repel each other and would build
nothing.
• But electrons are attracted to protons.
• Ordinary
atoms have identical numbers of
electrons and protons making them
electrically neutral overall.
•Isotopes
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.
•
•Atoms
Atom Models
Thomson Model, 1904
- “plum pudding” model
- does not distinguish a nucleus or
electron orbits (shells)
•Atoms
Atom Models
Rutherford Model, 1911
- nucleus with orbital rings
•Atoms
Atom Models
Bohr Model, 1913
- nucleus with rings around it
– easy to use and understand
carbon
nitrogen
hydroge
n
•Atoms
Atom Models
Lewis Structure, 1916
- chemical symbol surrounded with
dots representing valence electrons
(rather than rings)
used in chemical formulas to represent
behavior of atoms
oxygen
water
•Atoms
Atom Models
electron cloud Model, 1920’s
- based on x-ray technology
•Atoms
Studying Atoms
atoms ato
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
atoms
scientists can still only see the electron
cloud even with the best technology
to
reactions
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
•Molecules
• Consists
of two or more atoms joined in
a definite ratio.
• Most are composed of atoms of two or
more elements.
• An element is a substance that cannot
be broken down into any other
substances by chemical or physical
means.
•Molecules
•A
molecule consists of two or more
atoms of the same element, or different
elements, that are chemically bound
together.
• Diatomic molecules are made of two
atoms of the same element.
• Hydrogen
– H2
• Oxygen – O2
• In the animation above, two nitrogen atoms
(N + N = N2) make one Nitrogen molecule .
•Covalent Bonding




When atoms share one or more pairs of
electrons.
Example: Oxygen shares one of its
electrons with each of the two hydrogen
atoms.
Oxygen’s outer shell is now filled with 8
electrons.
Each hydrogen atom share its 1 electron
with the oxygen atoms so they now have
2 electrons in their outer level.
http://faculty.clintoncc.suny.edu/facult
y/michael.gregory/files/bio%20101/bio
%20101%20lectures/chemistry/chemistr.
htm