(Nuclear Reactions –
Fusion & Fission;
Forces in the Nucleus)
(Periods 1, 2, 4 Only)
Chemical reactions
valence
electrons
involve the ___________
of the atom.
Nuclear reactions
nucleus
involve the __________
of the atom.
Date
Date Date Into
Issued Due Grade
Book
Assignment
Currently Open
Summative
or
Formative
QUIZ – ACIDS, BASES, and
pH
S
3/9
3/9
WS – Acid-Base Strength
F
3/19
3/21
WS – Neutralization
Reactions
F
3/21
3/23
QUIZ - Strength of Acids &
Bases, Neutralization, Acid
Rain
S
3/23
3/23
3/9
Last
Day
3/30
Announcements
Can you make an element like gold?
Making an element is possible only if
you can achieve a nuclear reaction.
Nuclear reactions involve either
combining or splitting the nuclei of
atoms.
Gold (Au) has an atomic
number of 79, meaning
there are 79 protons in the
nucleus of all gold atoms.
Which atoms do you
think could be
combined to make
gold?
Fusion and Fission
To make gold,
you would need
to perform a
nuclear reaction.
There are two
kinds of nuclear
reactions:
fusion
fission
The process of
combining the nuclei of
atoms to make different
atoms is called
•Fusion
Breaking up the nucleus of an atom is
called fission.
Scientists can use
a special machine
called a particle
accelerator to
bombard particles
and atoms in
order to achieve
fusion and fission
reactions.
Only a very small
number of atoms
can be made in
this way at one
time.
Protons are
positively
charged
particles.
Ex) Boron atomic number
5.
The nucleus of a
boron atom has
five positively
charged
protons.
What keeps
these positive
particles
together?
The nucleus stays together because of the strong
nuclear force.
The strong nuclear force attracts every proton and
neutron to every other proton and neutron.
The attractive forces from the neutrons and protons
together are stronger than the electromagnetic
force that cause the protons to repel each other.
For every atom heavier
than hydrogen there
needs to be at least as
many neutrons as
protons to hold the
nucleus together.
For heavier
atoms, more
neutrons are
needed than
protons.
Ex) Calcium40 has 20
protons and
20 neutrons.
For atoms
with more
than 83
protons,
even the
added
strong
nuclear
force from
neutrons is
not enough
to hold the
nucleus
together.
Every
nucleus
with more
than 83
protons is
unstable.
Remember
that atoms
in an
element
can have
different
numbers of
neutrons.
Ex) All
carbon
atoms
have six
protons,
but some
have six
neutrons
and some
have seven
neutrons.
Remember, atoms of the same
element that differ in their number of
neutrons are called isotopes.
Ex) A carbon atom with six neutrons is
referred to as carbon-12 and one with
seven neutrons is carbon-13.
The atomic mass number of an
isotope is the number of protons plus
the number of neutrons in an atom.