What does it mean to fuse something together When hear word fission what does it mean Formation of Elements I How Elements Form A Nuclear Fusion when two atomic nuclei combine ID: 915674
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Slide1
Think – Don’t Speak.
What does it mean to
fuse
something together?
When hear word
fission
– what does it mean?
Slide2Formation of Elements
Slide3I. How Elements Form
A.
Nuclear Fusion
– when two atomic nuclei combine
1. energy is released 2. a new element is formed
Video: How are Elements Formed?
www.youtube.com/watch?v=neMEo8ZrwuI
Slide4Slide5II. Fusion in Stars
A. Stars begin as hydrogen atoms, the
H
fuses to make heavier elements.
B. Energy is given off in light, heat, and radiation.
Slide6Slide7http://www.youtube.com/watch?v=neMEo8ZrwuI
5 min clip
Slide8Nuclear Reactions
Alpha, Beta, and Gamma Decay
Slide9The Atom
The atom consists of two parts:
1. The nucleus which contains
:
2
. Orbiting electrons.
protons
neutrons
The
mass
of an atom is almost entirely due to the number of protons and neutrons.
Slide10X
A
Z
Mass number
Atomic number
Element symbol
= number of protons +
number
of neutrons
=
number of protons
Slide11X
A
Z
Mass #
=
number of protons + number of neutrons
Atomic #
=
number of protons
Mass #
---
Atomic #
#neutrons
Slide12U
235
92
U
238
92
There are many types of uranium
:
Mass #
Atomic #
Number of protons
Number of neutrons
Number of electrons
Mass #
Atomic #
Number of protons
Number of neutrons
Number of electrons
ISOTOPES
Slide13U
235
92
U
238
92
There are many types of uranium:
Mass #
235
Atomic #
92
Number of protons
92
Number of neutrons
143
Number of electron
92
Mass #
238
Atomic #
92
Number of protons
92
Number of neutrons
146
Number of electron
90
2+
Slide14Most of the isotopes which occur naturally are
stable.
A few naturally occurring isotopes and all of
the man-made
isotopes are unstable.Unstable isotopes
can become stable by releasing different types of particles.
This process is called
radioactive decay
and the elements which undergo this process are called
radioisotopes/.
Slide15Radioactive decay results in the emission of either
:
an alpha particle (
a
), a beta particle (b
),
or a gamma
ray
(
g).
Radioactive Decay
Slide16An alpha particle is identical
to
that of a
helium nucleus.
It contains
2
protons
and 2 neutrons
.
Alpha Decay
Slide17Alpha Decay
Ra
226
88
Rn
222
86
He
4
2
Slide18X
A
Z
Y
A - 4
Z - 2
+
He
4
2
Ra
226
88
Rn
222
86
+
He
4
2
Alpha Decay
Slide19Rn
222
86
He
4
2
+
Po
218
84
He
4
2
Rn
222
86
+
Y
A
Z
He
4
2
Alpha Decay
Slide20He
4
2
U
234
92
+
Th
230
90
He
4
2
X
A
Z
+
Th
230
90
He
4
2
Alpha Decay
Slide21Th
230
90
+
Y
A
Z
He
4
2
Alpha Decay
He
4
2
+
Ra
226
88
He
4
2
Th
230
90
Slide22Rn
222
86
He
4
2
+
Po
218
84
He
4
2
Rn
222
86
+
Y
A
Z
He
4
2
Alpha Decay
Slide23X
A
Z
+
Pb
214
82
He
4
2
Alpha Decay
He
4
2
+
Pb
214
82
He
4
2
Po
218
84
Slide24Beta Decay
A beta particle is a fast moving
electron
which is emitted from the nucleus of an atom undergoing radioactive decay.Beta decay occurs when a neutron
changes into a proton and an electron.
Slide25Beta Decay
As a result of beta decay, the nucleus
has
1
less neutron, but 1extra proton.
The atomic number,
increases
by
1
and the mass number,
stays
the same
.
Slide26Beta Decay
Po
218
84
b
0
-1
At
218
85
Slide27X
A
Z
Y
A
Z + 1
+
b
0
-1
Beta Decay
Po
218
84
At
218
85
+
b
0
-1
Slide28Th
234
90
Y
A
Z
+
b
0
-1
Beta Decay
Th
234
90
Pa
234
91
+
b
0
-1
Slide29X
A
Z
Pb
210
82
+
b
0
-1
Beta Decay
Tl
210
81
Pb
210
82
+
b
0
-1
Slide30Bi
210
83
Y
A
Z
+
b
0
-1
Beta Decay
Bi
210
83
Po
210
84
+
b
0
-1
Slide31Gamma Decay
Gamma rays are not
charged particles
like
a and b particles.
Gamma rays are electromagnetic radiation with
high
frequency.
When atoms decay by emitting
a
or
b
particles to form a new atom, the nuclei of the new atom formed may still have too much energy to be completely stable
.
This excess energy is emitted as
gamma
rays
Slide32Slide33Slide34III. Synthetic Elements by Humans
A.
Synthetic Element
– human-made, not formed in nature.
B. Natural Element – forms by natural processes
Slide35Slide36Synthetic Elements
Slide37C. Synthetic elements are made by smashing atoms together in a
particle accelerator
.