TOPIC: Radioactivity

Do Now: Take out your notes from Monday, and get ready for an open notebook quiz

Not all isotopes are stable

Stable isotopes have…

1:1 ratio of n0 to p+ (for elements <20)

1.5:1 ratio of n0 to p+ (for elements >20)

To determine if an isotope is stable or unstable (radioactive) – compare the number of protons to neutrons

Beyond Element 83 are very unstable (radioactive)

• No amount neutrons can hold nucleus together once it has 83+ protons

• All Elements 83 and above on PT are radioactive

• Other elements may have radioactive isotopes applet

Radioisotopes- unstable nucleus – they are radioactive

the nucleus of element emits radioactive particles and/or electromagnetic waves…by emitting these particles,nucleus changes into different element (it’s trying to become more stable)

Radioactive Decay Series

• Sometimes 1 change isn’t enough to achieve stability

• Some radioisotopes go through several changes before they achieve stability (and are no longer radioactive)

U-238 PB-206