Spontaneous Decay Flashcards
What are 3 different types of radioactivity?
alpha, beta and gamma (a,b and y)
What are the characteristics of alpha (𝛼) particles?
Helium nuclei (2 protons + 2 neutrons).
Low penetration (stopped by paper).
High ionization power (no electrons 2+ charge).
Speed up to 20% of light.
What are the characteristics of beta (𝛽) particles?
Electrons (much lighter than alpha particles).
Higher speed (approaching the speed of light).
Moderate penetration (stopped by aluminum).
Lower ionization power than alpha particles.
help reach stability line - neutron-to-proton ratio (N/Z).
FOR BETA + - POSITRON AND BETA - REGULAR ELECTRON
What are the characteristics of gamma (𝛾) rays?
Electromagnetic radiation with short wavelength.
Very weak ionization power.
Extremely high penetration (can pass through 10 cm of lead).
How do alpha (𝛼) particles behave in a magnetic field?
Deflected in one direction due to their positive charge (+2).
Heavier than beta particles, so they curve less.
better:
Due to their positive charge, alpha particles are deflected in a magnetic field. They curve less than beta particles because of their higher mass (around 4 atomic mass units).
How do beta (𝛽) particles behave in a magnetic field?
Deflected in the opposite direction to alpha particles due to their negative charge (-1).
Much lighter, so they curve more sharply than alpha particles.
NOTE - BETA PLUS GOES IN SAME DIRECTION AS ALPHA AND BUT WITH GREATER CURVATURE BECAUSE LIGHTER
How do gamma (𝛾) rays behave in a magnetic field?
Not deflected because they are neutral (no charge).
Travel straight through the field.
What is nuclear transmutation?
Nuclear transmutation is when the nucleus of an atom changes into a different element or isotope.
Types of Nuclear Transmutation:
Natural Transmutation (Spontaneous decay):
Happens naturally in unstable nuclei.
Examples: Alpha, Beta, and Gamma decay.
The nucleus changes by emitting radiation, leading to a new element or a more stable state.
Artificial Transmutation (Induced reactions):
Happens when a nucleus is bombarded with particles (like protons, neutrons, or alpha particles).
Example: Rutherford’s experiment (1919), where he bombarded nitrogen with alpha particles to produce oxygen and a proton.
Used in nuclear reactors, particle accelerators, and nuclear weapon research. NOTE - ALL NUCLEONS IS CONSERVED, CHARGE IS CONSERVED, SUM OF LEFT IS = TO SUM OF RIGHT CHARGES, MASS ENERGY IS CONSERVED.
What is alpha decay?
Alpha decay occurs in very heavy nuclei (high atomic and mass numbers) because the strong nuclear force weakens, and electrostatic repulsion between protons increases, making the nucleus unstable. To regain stability, the nucleus emits an alpha particle (2 protons and 2 neutrons), reducing its atomic number by 2 and mass number by 4. This shifts the nucleus down and left on the stability graph, bringing it closer to the stable region.
What is beta + decay?
A proton transforms into a neutron, and the nucleus emits a beta-plus particle (positron, e⁺) and a neutrino (ν).
Atomic number (Z) decreases by 1 (proton lost).
Mass number (A) stays nearly the same (proton → neutron swap).
Shifts the nucleus up and left on the stability graph, correcting too many protons.
What is beta - decay?
ALL BETA DECAYS HAPPEN BECAUSE OF INSTABILITY
A neutron transforms into a proton, and the nucleus emits a beta-minus particle (electron, e⁻) and an antineutrino (ν̅).
Atomic number (Z) increases by 1 (new proton added).
Mass number (A) stays nearly the same (neutron → proton swap).
Shifts the nucleus down and right on the stability graph, correcting too many neutrons.
How does instability lead to decay?
Too many neutrons (high N/Z) → Beta-minus (β⁻) decay (neutron → proton).
Too many protons (low N/Z) → Beta-plus (β⁺) decay or electron capture (proton → neutron).
Very high Z nuclei → Alpha (α) decay to reduce both protons and neutrons.
This N/Z ratio determines whether an isotope is stable or undergoes radioactive decay.
(N/Z) NEUTRON TO PROTON RATIO
What is gamma radiation?
After alpha or beta decay, the new nucleus might have excess energy.
Instead of changing the number of protons or neutrons, the nucleus releases this excess energy as gamma radiation (γ).
This allows the nucleus to transition from a higher energy (excited) state to a lower (stable) state.
List what can go through paper, aluminum and lead with reasoning.
alpha stops at paper, beta stops at aliminium and gamma goes through all
EVEN THOUGH BETA IS LIGHTER, IT TRAVELS AT A FASTER SPEED AND IT’S LIGHTER COMPARED TO ALPHA. GAMMA CAN GO THROUGH BECAUSE THEY HAVE NO CHARGE OR MASS WITH HIGH ENERGY, MAKING THEM PENETERABLE.
