Transcript Unit 2 Chapter 3

Unit 2
Chapter 3
Matter
and Atomic
Structure
VOCAB
WRITE ALL VOCAB WORDS DOWN BEFORE YOU
START YOUR DEFINITIONS!!
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Matter
Periodic table
Atom
Proton
Neutron
Element
Solid
Liquid
Gas
Sublimation
Evaporation
Ionic Bond
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Covalent bond
Acid
Base
Condensation
Solution
Homogenous
mixture
• Heterogenous
mixture
VOCAB DUE: MONDAY 9/14
Section 1
• Objectives:
–Describe the particles within atoms
and the structure of atoms.
–Relate the energy levels of atoms to
the chemical properties of
elements.
–Define the concept of isotopes.
What is matter?
• Matter is anything
that has volume and
mass.
• On earth these are found
as solids, liquids and gas.
• Everything on Earth and beyond
is made of substances called
elements.
What is an ELEMENT?
• An element is a substance that
cannot be broken down into
simpler substances by
physical or chemical means.
Example
• If I were to melt gold necklace in a pot it
would no longer be solid but it would still
be gold. No matter what form it’s still gold!
Elements
• There are 92 natural elements
Elements that were present in
•ancient
Others have
been
artificially
created
times
have
different
•symbols,
All elements
are
identified
by
a
that represent their
chemical symbol that is 1-3 letters
latin
Like Gold
with the
long.origin.
(Ex: H stands
for Hydrogen)
the latin
word
•symbol
They areAu
all for
grouped
together
in the
periodic table!
Aurum.
• Each element has
distinct characteristics.
• Elements are made up
of atoms.
What is an Atoms?
• Atoms are the smallest particle
of an element that has all the
characteristics of that element.
• Consists of protons, electrons
& neutrons and a nucleus in
the center.
• Nucleus- the center of an
atom. Made up of protons &
neutrons.
• Proton- a tiny particle that
has a mass & a positive
electrical charge.
• Neutron- has the same mass
as the proton, but electrically
neutral.
•All nuclei are
positive. WHY?
Because they are made up
of positive protons and
neutral neutrons.
All atoms contain different numbers of
protons and neutrons.
– Hydrogen – smallest atom
• Hydrogen only has 1 proton in the nucleus
– Uranium- heaviest
• Uranium 238 has 92 protons and 146 neutrons
• Number of protons in an atoms
nucleus is the atomic number
–Ex. Carbon has 6 protons so therefore
it’s atomic number is 6
• Number of protons + neutrons = atomic
mass or mass number
–Ex. Carbon has 6 protons and 6
neutrons for a atomic mass of 12
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~ELECTRONS~
• Electrons
• Although they are really tiny they have
a electrical charge that is NEGATIVE!
• That charge is the exact same
magnitude as the proton.
• ATOMS HAVE THE SAME NUMBER
OF PROTONS AND ELECTRONS!!
• So since 1 electron has the same
charge as 1 proton and there are the
same amount of each. What would
be the over all charge of an atom??
So since 1 electron has the
same charge as 1 proton
and there are the same
amount of each. What
would be the over all charge
of an atom??
NONE! ZIP! ZERO! NADA!!!
It has NO charge!!!
What are ENERGY LEVELS?
• Energy levels
represent the area in
an atom where an
electron is most likely
to be found.
This is a silver atom
These are
different
energy levels
12
10
11
1
9
2
13
14
8
7
1
3
8
6
15
5
4
16
2
7
4
5
17
18
6
1
2
3
• These energy levels are kind of like
bedrooms in a house. Different houses
have different number of bedrooms and
can sleep different number of people.
• Each energy level can only hold so many
electrons. The larger the energy level the
more electrons it can hold.
• The smallest energy level can only
hold 2 electrons.
• The second energy level can hold 8
• The 3rd can hold 18 and the 4th can
hold 32!
• Some atoms can have up to 7 energy
levels!!!
• Each level is larger than the last and
has more room for more electrons,
just like bigger houses have more
room for bigger families!
• Electrons always want to have their energy
levels full so they will occupy the lowest
available level.
• The electrons in the outermost energy level
determine the chemical behavior of the
elements.
• The outermost electrons are called
VALENCE ELECTRONS!
• Elements with the same number of valence
electrons have similar properties.
• Elements with 1 valence electron are
very reactive like Potassium and Sodium,
they combine well with other elements.
• Because they want to fill their energy
levels!
• If an elements energy levels are full it is
inert, which means it doesn’t react
easily with other elements.
• Helium, Neon and Argon are inert
Because their energy levels are all full!
• You can find out much of this information
just by looking at your periodic table!!
What are ISOTOPES?
• Atoms of the same element with
different mass numbers.
• We know that all atoms have the same
number of protons but they don’t always
have the same number of neutrons!
What is ATOMIC MASS?
•The average of the
mass numbers of
the isotopes of an
element.
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The nucleus of some
isotopes is unstable and
release RADIOACTIVITY!!!!
Radioactivity is the
spontaneous process
through which unstable
nuclei emit radiation.
FUN FACTS!!!
During radioactive decay, a nucleus can lose
protons and neutrons, change from proton
to neutron or vice versa, this changes the
identity of the element.
EX: Uranium 236 decays to Lead 206 and
Uranium present in rock is eventually
replaced with lead. By measuring the
amount of uranium and lead in rocks we
can determine their age!!!