Isotopes & Radioactive Decay Unit 7.1

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

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

There are two ways to represent isotopes:

92 235 92 143 92 238 92 146 Uranium-238

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

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%

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

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

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

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

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

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

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

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

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

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

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

Alpha Decay (a) 2p and 2n 4

Alpha Decay (a)

Beta Decay (b) electron p + e

Beta Decay (b)

Gamma Decay (g) energy gamma ray

Gamma Decay (g)

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

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