Atoms
Name the 3 subatomic particles in an atom
Proton, neutron, electron
Isotopes of a given element will have a different number of this particle
Neutrons
What are the 3 types of decay?
Alpha, beta, gamma
What does the half life tell us?
How long it takes for half of an elements material to decay
When will an atom be unstable?
When there are too many or too few neutrons
Where are the protons located?
The nucleus
What does the 12 in Carbon-12 represent?
The mass number
Rank the types of radioactive decay from strongest to weakest
1.gamma
2. beta
3. alpha
What does this mean “The half life of Caesium-137 is 30 years”?
The half life of Caesium-137 is 30 years means that it will take 30 years for half of the material to decay to a more stable form.
What are the 2 types of nuclear reactions and how are they different?
Fission = 1 nucleus separating into 2
Fusion = 2 nuclei combining to form 1
Where are electrons located?
Electron cloud
Isotopes are elements with the same atomic ______ but different atomic ______
Isotopes are elements with the same atomic numbers but different atomic mass
State the changes that occur as a result of alpha decay
Mass number decreases by 4
Atomic number decreases by 2
If an isotope starts with the radioactivity of 80 counts/min, how much will be left at its half life?
40 counts/min
What will a radioactive isotope emit if there are too many neutrons?
a beta particle
If there are 12 electrons, how many protons are there?
12
What do carbon-12 and carbon-13 have in common?
Same number of protons
Identify the type of decay in the equation below
131I --> 131Xe + 0e
53 54 -1
beta decay
How much substance remains after 2 half lives?
1/4
What is an alpha particle?
2 protons and 2 neutrons
Protons + Neutrons =
atomic mass of an atom
An atoms Mass Number is 30.... Keeping in mind that the atomic number is 17, what can you tell about the atom? (Hint: How do you find the number of neutrons?)
It has 13 neutrons
Mass number - atomic number = neutrons
= 30 - 17= 13
Write the decay equation for gamma decay on this element
87Sr
32
no change in atomic mass or atomic number
gamma ray released
What is the half life of this element? (see graph)
6 days
The group number on the periodic table tells us how many ________ an atom has
Valence electrons