Understanding Radioactive Decay: Neutron-Proton Ratio and Stability of Nuclei, Slides of Chemistry

Download Understanding Radioactive Decay: Neutron-Proton Ratio and Stability of Nuclei and more Slides Chemistry in PDF only on Docsity!

Radioactive Decay

Nuclear Stability

• The most stable nuclei are those that have a

neutron to proton ration of 1:

• How do we know how many neutrons and protons

an atom has?

Examples

• What is the stability of 4

2 He

-^8034 Se -^12151 Sb

• Of the 3 examples

above, which is the

most stable?

Radioactive Decay

• The spontaneous disintegration of a nucleus into a slightly lighter nucleus

Types Sym Charge

• Alpha 42 He +
• Beta (^0) -1β -
• Gamma γ 0

Example

• Radium – 226 has a half life of 1,600 years.

There is a 32 mg sample of Radium – 226 that

is decaying. How many half lives will It take

for that sample to decay to 1 mg? How many

years would it take?

Example 2

• Exactly 1/16 of Radium – 226 remains after 24 years.
• a) What is the half life?
• b) if there is a 50.0 g sample left after 24 years, what was the original amount?
• c) How much has decayed after 18 years?