writing decay equations 19.1. radioactivity radioactive decay is the loss of energy to achieve...
TRANSCRIPT
Writing Decay Equations19.1
Radioactivity
• Radioactive decay is the loss of energy to achieve stability– Spontaneous process– Where unstable isotopes of one element
transform into stable isotopes of another element
Particles produced determine type of decay
A Review From Friday
•Which of the following represents alpha, beta and gamma decay?
He42 0
0e01alpha gamm
abeta
Types of Radiation
How do we know what the charge is of each type of radiation?
Steps for Writing Nuclear Equations
•Example: produces a β particle–Write what you know:
–Solve for the missing piece!!
–BIG HINT!!!•The total mass and total atomic number have to be the SAME on BOTH sides of the equation!!!
Bi21483
____01
21483 eBi
Writing Nuclear Equations
• Example: Breakdown of radium by alpha decay
• Try to write the equation for the alpha decay of thorium-230.
RnHeRa 21886
42
22288
RaHeTh 22688
42
23090
Writing Nuclear Equations
• Try to write the equation for the beta decay of Ac-227.
• Write the equation for the alpha decay of U-238 in which a gamma ray is produced
TheAc 22790
01
22789
00
23490
42
23892 ThHeU
Writing Nuclear Equations
• Write the decay equation for Na-22 by positron emission
• Try to write the equation for the positron decay of K-38.
NeeNa 2210
01
2211
AreK 3818
01
3819
Writing Nuclear Equations
• Write the decay equation of mercury-201 through electron capture
• Write an equation for the electron capture by Ni-59.
00
20179
01
20180 AueHg
Co Ni 5927
01-
5928 e
Solving Nuclear Equations
•For each of the following, supply the missing particle:
____
____3818
3819
19578
19579
ArK
PtAu
X-rays are not NUCLEAR radiation
• X-rays– Behave the same as
gamma rays• Difference not
given off in radioactive decay
– Lower energy electromagnetic rays
– Occur when inner e- are kicked our and outer e- drop down to fill the vacancy
Before the lab activity
• We will be looking at amount of radiation in this class lab.
• How do we detect radiation?
Measuring Decay: Geiger Counter
• High-energy particles from radioactive decay produce ions when they travel through matter
• The probe of the Geiger counter contains argon gas that have no charge but can be ionized by the rapidly moving particle
• Momentarily allows a “pulse” of current to flow
• Counts the pulse events and records
Figure 19.2: A representation of a Geiger-Müller counter.
Measuring Decay
• Scintillation Counter– Uses substances that give off light when
struck by high-energy particles– Detector counts the flashes of light to
determine number of decay events
Penetrating power of radioactive emissions.
Penetrating power is inversely related to the mass and charge of the emission.
AKA: Bigger the particle, the easier it is blocked
Big particle small particle