1. Isotopes, Radioactivity, Decay

2. _______________________
An atom of the __________________________ with a different number of __________________
Examples
Carbon-12 has 6 protons and 6 neutrons
6 protons + 6 neutrons = 12 (mass number)
Carbon-14 has 6 protons and 8 neutrons
6 protons + 8 neutrons = 14 (mass number)

3. Hydrogen normally has 1 proton (Also called protium)
_______________________________
Hydrogen sometimes has 1 proton and 1 neutron (deuterium)
Hydrogen can also have 1 proton and 2 neutrons (tritium)

4. Which ones are isotopes?
Uranium-238
Iodine-131
Xenon-131
Hydrogen-2
Uranium-235
Hydrogen-1

5. O O Review way to show atoms and ions
Shows atomic #, mass #, and neutrons
Preferred way
Mass # = _______
Atomic # = ______
Neutrons = _____
Electrons = _____
Protons = ______
Mass # = _______
Atomic # = ______
Neutrons = _____
Electrons = _____
Protons = ______ 16 17 O O 8 8

6. Radioactivity
Process by which an _______________________________emits one or more _______________________________ or wavelike high energy
Particles that are released from the _____________________________ during radioactive decay is called _____________________________
There are different types of nuclear radiation:
_______________ – 2 protons & 2 neutrons
Stopped with a piece of paper
_______________ – electron
Stopped by aluminum shielding
_______________ – high energy waves
Stopped by thick layer of lead or concrete

7. ______________________ is used to date materials.
Radioactive Decay
________________________
______________ required for half of a sample of a _____________________ substance to disintegrate by radioactive decay or by natural processes.
Half-life is a measure of how quickly a substance decays.
Using half-lives, scientist can predict how ___________ an object is.
______________________ is used to date materials.

8. Carbon-14 has a half-life of 6,000 years
Half-life Practice
Carbon-14 has a half-life of 6,000 years
If there is originally 100 atoms of carbon-14, how many are there after 6,000 years?
_______________________________
How about 12,000 years?
How about 18,000 years?