Isotopes and Nuclear Radiation Flashcards
Atomic Structure (16 cards)
What are isotopes?
Atoms with the same number of protons but a different number of neutrons
Isotopes have the same atomic number but different mass numbers.
What defines the atomic number of an element?
The number of protons in its nucleus
Each element has a unique atomic number.
What is the mass number of an atom?
The number of protons plus the number of neutrons in its nucleus
It reflects the total mass of the atom’s nucleus.
How many stable isotopes do most elements have?
Usually one or two stable isotopes
Other isotopes tend to be unstable.
What is radioactive decay?
The process by which unstable isotopes decay into other elements and emit radiation
This process helps isotopes become more stable.
What types of radiation are emitted by radioactive substances?
Alpha, beta, and gamma radiation
These are the types of radiation you need to know.
What is ionizing radiation?
Radiation that knocks electrons off atoms, creating positive ions
The ionizing power indicates how effectively a radiation source can ionize atoms.
What constitutes an alpha particle?
Two neutrons and two protons
An alpha particle is essentially a helium nucleus.
How far can alpha particles travel in air?
A few centimeters
Alpha particles are quickly stopped by materials like paper.
Why are alpha particles strongly ionizing?
Due to their size
They can cause significant ionization when interacting with matter.
What is a beta particle?
A fast-moving electron released by the nucleus
Beta particles have virtually no mass and a charge of -1.
How do beta particles interact with materials?
They penetrate moderately far and can travel a few meters in air
They are absorbed by materials like a sheet of aluminum (around 5 mm thick).
What happens to a neutron in the nucleus when a beta particle is emitted?
It turns into a proton
This process changes the element into a different one.
What are gamma rays?
Waves of electromagnetic radiation released by the nucleus
Gamma rays have high penetration power and can travel long distances through air.
Why are gamma rays considered weakly ionizing?
They tend to pass through atoms rather than collide with them
Eventually, they can cause damage when they interact with matter.
What materials can absorb gamma rays?
Thick sheets of lead or meters of concrete
These materials are effective at shielding against gamma radiation.
