1. Isotopes & Radioactive Decay
Unit 7.1

2. Review # of protons # p + # n average mass nucleus 1 +1 nucleus 1
shells -1
# of protons
# p + # n
average mass

3. neutrons
Isotope: an element with a different number of ________________ (and different mass number)

4. There are two ways to represent isotopes:

5. 92
235 92
143 92
238 92
146
Uranium-238

6. 92
235 92
143 92
238 92
146
Uranium-238 6 12 6 6 6 14 6 8
Carbon-14

7. Why is atomic mass not a whole number? Where does atomic mass come from? Remember, atomic mass is the average mass of an element. 35
75% 37
25%

9. unstable radioactive decay radiation
Some isotopes are stable and do not change overtime. Some isotopes are ______________ and break down over time. This breakdown is called ____________________________________. The products of the break down are collectively called ____________________.
unstable
radioactive decay
radiation

11. alpha radiation (a) helium atom or beta radiation (b) electron or
Name
Characteristic
Particle Emitted
Nuclear Formula
has mass and size
only has energy
-----
alpha
radiation (a)
helium atom or
beta
radiation (b)
electron or
gamma
radiation (g)
neutron
proton or H
nucleus or

13. There are 7 types of electromagnetic radiation:
Radiowaves (how the radio works)
Microwaves (we heat food with this)
Infrared (remote controls)
Visible Light (we can see this one)
Ultraviolet (from the sun)
X-Rays (to see our bones)
Gamma Rays

14. Review What is an isotope? An element with a different #p
An element with a different #n
An element with a different #e
A word

15. Review What is a radioactive isotope? An isotope that is inactive
An isotope that is active
An isotope that is unstable
An isotope that likes to listen to music and break dance

16. Review What is radioactive decay?
The breaking down of an unstable isotope
The breaking down of a stable isotope
When an isotope becomes a, b, or g
When an isotope goes bad

17. Review What is radiation? Heat and energy
Energy and particles emitted from radioactive decay
Particles emitted from an isotope
Nuclear bomb!

18. Review
What is the symbol for beta radiation? bb aa ag l b a g 

19. x = w + r
y = z + s
y ≠ z
Transmutation: when an element changes because of a gain or loss in protons.

20. 17 13 4 8 6 2 → ? + Mass Number = Atomic Number Element: O He
k Example → ? +
Mass Number =
Atomic Number
Element: O He 17 13 4 8 6 2

21. k Example: Complete the following radioactive decay equation.72 Ga 31

24. Alpha Decay (a)
2p and 2n 4

25. Alpha Decay (a)

26. Beta Decay (b)
electron
p + e

27. Beta Decay (b)

28. Gamma Decay (g)
energy
gamma ray

29. Gamma Decay (g)

30. go through Properties of Radiation
Different kinds of radiation have different abilities to penetrate (____________________) materials
go through

32. a 2+ 4 He b 1- e- g - slowest, heaviest - does not penetrate easily
- transmutation
- very small mass
very
small b 1- e-
- penetrates some things
- transmutation
- no mass, fastest g
high
energy
- penetrates the best
- no transmutation