Nuclear Reaction

Isotopes

Atoms of the same element having different number of protons and neutrons

Mass number

The sum of an atoms protons and neutrons

Atomic number

The number of an atoms protons

can be found in the periodic table

Radioactive Isotope (Radioisotope)

This isotope is unstable and spontaneously emits energy to stabilize its nucleus

Radioactivity

Nuclear Radiation emitted by radioisotope

Artificial Isotope

This Isotope do not exist naturally and are created by scientist in laboratories.

Alpha (α) particle

This particle is a high energy particle with 2 protons and 2 neutrons

• charge: +2

• Mass number: 4

Beta (β) particle

This particle has high energy electron

• Formed when a neutron is converted to a proton and an electron

• Charge: -1

• Mass: Negligible compared to proton

Positron (β+) Particle

Antiparticle of Beta Particle (opposite charge but same mass)

• Formed when proton is converted into a neutron

• Charge: +1

Gamma Ray γ

high energy radiation released from radioactive nucleus

Effects of Radioactivity - Damage

Nuclear radiation will damage or kill rapidly dividing cells

• bone marrow

• skin

• reproductive system

• intestinal system

Effects of Radioactivity - Cancer cells

Cancer cells divide rapidly (effect treatment for cancer)

Effects of Radioactivity - Food

Radioactivity towards food

• exposed to gamma rays

• Effect: kills microbes, parasites & insects

• Safety: food will not become radioactive

• Benefit: longer shelf life + safer to eat

Nuclear Reactions - radioactive decay

Unstable radioactive nucleus emits radiation

Nuclear reactions - nuclear equation

Original Nucleus → New Nucleus + radiation emitted

Alpha Emission 

This type of emission is the decay of a nucleus by emitting an alpha particle

• Mass ↓4

• Atomic number ↓2

Beta Emission

This type of emission is the decay of a nucleus by emitting beta particle

• 1 neutron is lost and 1 proton is gained

• Atomic number ↑1

• Mass: stays the same

Positron Emission 

This type of emission is the decay of a nucleus by emitting a positron particle 

• 1 proton is lost and 1 neutron is gained

• Atomic number: ↓1

• Mass: Stays the same

Gamma Emission 

This type of emission is the decay of a nucleus by emitting Gamma Radiation 

• γ rays are a form of energy only

• γ emission accompanies alpha or beta emission

• NO CHANGES

Balancing Nuclear Reactions - Step One

Write an equations with the original nucleus on the left, and the particles emitted on the right

Balancing Nuclear Reactions - Step Two

Calculate the mass number and atomic number of newly formed nucleus on the right

Balancing Nuclear Reactions - Step Three

Use the atomic number to identify the new nucleus and complete the equation

Half Life

Half-life (t1/2)

• time it takes for one half life of a sample to decay

• Independent of sample amount

• Does not change with temp

• Does not change with pressure