Ch30 The Atom, Nucleus and Radioactivity Flashcards
Who discovered the nucleus?
What was their experiment?
Rutherford
Bombarding gold foil with alpha particles
DEFINE emission spectrum?
The resulting pattern when light from a luminous source undergoes dispersion
DEFINE energy level?
The fixed amount of energy an electron in an atom can have
What does LASER stand for?
Light Amplification by Stimulated Emission of Radiation
What is the atomic number of an element?
Z, number of protons = electrons
What is the mass number of an element?
A, total mass of protons + Neutrons
DEFINE isotopes
Atoms of an element that have the same atomic number but different mass numbers due to differing numbers of neutrons
DEFINE radioactivity
The disintegration or decay of the nuclei of certain atoms with the emission of one or more types of radiation
What are the 3 types of radiation?
Alpha α , Beta β , Gamma γ
What is a beta particle?
e 0, -1
a fast moving electron
What is an alpha particle?
He 4, 2
Fast moving Helium nucleus
Give 3 points about alpha particles.
- Least penetrating
- Most ionising
- Helium nucleus
- Can be stopped by a sheet of paper
Give 3 points about a beta particle.
- Fast moving electron
- More penetrating than alpha
- Less ionising than alpha
- Can be stopped by aluminium
Give 3 points about gamma radiation.
- No charge
- Most penetrating
- Least ionising
- Can be stopped by lead or 1m of concrete
What is the equation for alpha decay?
X (A, Z) -> He (4, 2) + Y (A - 4, Z - 2)
