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Clicker #
Name …………………………………………….
Team ……………………….
Title: Atoms and charges
Date ………………………
Using the diagrams below work out the overall charge on each of these Ions
Proton
Neutron
Electron
Overall charge____________________
*
Overall charge____________________
Looking at the nuclear structure of the atom answer the following questions
*
What is the mass number?
*
What is the atomic number?
* What group is the atom in?
* How many shells of electrons would the atom really have?
What period would the atom be in?
Identify the atom
Rapid Knowledge
Clicker #
Name …………………………………………….
Team ………………………
Title: Isotopes
Date ………………………
What are isotopes?
Magnesium has a ram of 24.33 amu there are 2 isotopes of magnesium 24 Mg and 25
Mg
Lithium has a ram of 6.9 amu there are 2 isotopes of lithium 6 Li and 7 Li
Vanadium has a ram of 50.9 amu there are 2 isotopes of Vanadium 50 V and 51V
Radioactivity
it?
All substance are made of atoms.
These have electrons (e) around the outside,
and a nucleus in the middle.
The nucleus consists of
protons (p) and neutrons (n),
and is extremely small.
(Atoms are almost entirely made of empty space!)
Rutherford’s gold foil experiment !!!!!
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This form of Lithium is NOT radioactive - it's
just an example of a simple atom.
Most radioactive substances
have many more particles in their nucleus
In some types of atom, the nucleus is unstable, and will decay into a more stable atom.
This radioactive decay is completely spontaneous.
It's not the same as what happens in a nuclear power station (where neutrons whizz
around and hit uranium nuclei, causing them to split).
.
^
You can heat the substance up, subject it to high pressure or strong magnetic fields - in
fact, do pretty much whatever you like to it - and you won't affect the rate of decay in
the slightest.
*
When an unstable nucleus decays, there are three ways that it can do so.
It may give out:
an alpha particle (we use the symbol

a beta particle (symbol

a gamma ray (symbol
)\
)
Many radioactive substances emit
In fact, you won't find a pure
and/or
too.
)
particles and
particles as well as
source: anything that gives off
rays.
rays will also give off
Alpha particles
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Alpha particles are made of 2 protons and 2 neutrons.
This means that they have a charge of +2, and a mass of 4
(the mass is measured in "atomic mass units", where each proton &
neutron=1)
We can write them as , or,
because they're the same as a helium
nucleus,
.
Alpha particles are relatively slow and heavy.
They have a low penetrating power - you can stop them with just a sheet of paper.
Because they have a large charge, alpha particles ionize other atoms strongly.
*
Beta particles
Beta particles have a charge of minus 1, and a mass of
about 1/2000th of a proton. This means that beta particles are the
same as an electron.
We can write them as or,
because they're the same as an
electron,
.
They are fast, and light.
Beta particles have a medium penetrating power - they are stopped by a sheet of
aluminum or plastics such as Perspex.
Beta particles ionize atoms that they pass, but not as strongly as alpha particles do.
*
Gamma rays
Gamma rays are waves, not particles.
This means that they have no mass and no charge. So we sometimes
write
.
Gamma rays have a high penetrating power - it takes a thick sheet of
metal such as lead, or concrete to reduce them significantly.
Gamma rays do not directly ionize other atoms, although they may
cause atoms to emit other particles which will then cause ionization.
We don't find pure gamma sources - gamma rays are emitted alongside alpha or beta
particles. Strictly speaking, gamma emission isn't 'radioactive decay' because it doesn't
change the state of the nucleus, it just carries away some energy.
Summary
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
Alpha particles are easy to stop, gamma rays are hard to stop.

Particles that ionize other atoms strongly have a low penetrating power,
because they lose energy each time they ionize an atom.

Radioactive decay is not affected by external conditions.

You need to know the information in this table:-
Type of Radiation
Symbol
Alpha particle
or
Beta particle
or
or
Gamma ray
(can look different,
depends on the font)
Mass (atomic mass
units)
4
1/2000
0
Charge
+2
-1
0
Speed
slow
fast
very fast (speed of
light)
Ionizing ability
high
medium
0
Penetrating power
low
medium
high
paper
aluminum
lead
Stopped by:
Notes
Information Sheet
More explaining
Diagrams
Definitions quotes and
smart phrases
Equations
Key points
Lecture Notes
More explaining
Diagrams
Definitions quotes and
smart phrases
Key points
Equations
Independent practice
Name ………………………………………
*
Title: Atoms and radiation
Team ……………………….
Date ………………………
1.
2.
3.
4.
5.
6.
Protons are ------------------ charged.
Neutrons have no charge.
Electrons are small and are ------------------ charged.
Protons & neutrons are in an atom’s -----------------Electrons are found in ------------------ around an atom’s nucleus.
The mass number is equal to an atom’s number of protons and ----------------- added together.
7. The atomic number is equal to the number of ------------------ in the
nucleus of an atom.
8. The number of neutrons = ------------------ – atomic number.
Isotopes are atoms with equal numbers of ------------------, but differ in their
------------------ numbers.
What are the following types of radiation made of
An alpha particle?
A Beta particle
A Gamma particle
*
In each case name the type of radiation that is emitted or absorbed
Reaction equation
1. 1H2 + 1H2 -> 2He4
1
Emitted
+ 13Al27 - > 11Na24 + 2He4
2.
0n
3.
13Al
4.
7N
27
14
+ 2He4 -> 15P30 + 0n1
+ 2He4 -> 1H1 + 8O17
Which reaction(s) from the list above is an example of:
Transmutation
^
^
Fusion
Which equation is an example of artificial transmutation?
1.
2.
3.
4.
^
238  He4 + Th234
92U
2
90
27
4
30
1
13AL  2He -> 15P + 0n
14
14
0
6C  7N + -e
226
4
 2He + 86Ra222
88Ra
In the reaction 4Be9 + X -> 6C12 + 0n1, the X represents
1.
2.
3.
4.
an alpha particle
a beta particle
an electron
a proton
Absorbed
Exit Ticket
*
Clicker #
Name ……………………………………………
Team ……………………….
Title:Atoms and radiation
Date ………………………
Which radioactive emanations have a charge of -1?
1.
2.
3.
4.
neutrons
gamma rays
alpha particles
beta particles
What kind of radiation will travel through an electric field on a pathway that remains
unaffected by the field?
1.
2.
3.
4.
a proton
a gamma ray
an electron
an alpha particle
Which particle cannot penetrate card?
1.
2.
3.
4.
alpha particle
beta particle
neutron
proton
Which particle is made up of a high energy electron?
1.
2.
3.
4.
alpha particle
beta particle
neutron
proton
In the reaction 4Be9 + X -> 6C12 + 0n1, the X represents
1.
2.
3.
4.
an alpha particle
a beta particle
an electron
a proton
Clicker #
HWK
*
Name …………………………………………
Team ……………………….
Title:Atoms and radiation
Date ………………………
1: Uranium isotopes have different:
A) atomic numbers
B) atomic masses
C) numbers of protons
D) numbers of electron
2. 2 State the number of neutrons and protons in each of the following nuclei:
a. 12 H :
________________________________________________________
b. 126 C :
________________________________________________________
56
Fe :
c. 26
_______________________________________________________
d. 197
79 Au :
_______________________________________________________
3.
radiation. Complete the table below with the correct information about each type.
Charge
Atomic Symbol
Can Be Stopped By
Alpha
Beta
Gamma
4. Which of the three radioactive emissions best fit the following statements?
Write the correct symbol/s on the lines.
a) These emissions are charged. ____________
b) This emission is the most massive (heaviest). ____________
c) This emission is the most charged. ____________
d) This emission is most dangerous outside of the body. ____________
e) This emission is stopped by thin paper or a few centimeters of air. _________
f) This emission can travel through paper, but is stopped by aluminum.
_______
g) This emission can travel through fairly thick lead. ____________
5. Which type of radiation – alpha, beta, or gamma:
a. Results in the greatest change in atomic number? Why?
__________________________________________________________________
b. Results in the least change in atomic number? Why?
__________________________________________________________________
c. Produces the greatest change in mass number? Why?
__________________________________________________________________
d. Produces the least change in mass number? Why?
__________________________________________________________________
6 What does this illustration represent?
A) a hydrogen nucleus and a helium nucleus
B) two hydrogen nuclei
C) two helium nuclei
D) two helium atoms