Nucleur Stability Flashcards
What’s Thompson’s Plum Pudding Model of the Atom?
In 1904 J.J. Thompson came up with the first modern model of the atom and introduced the notion of subatomic particles, it exhibited a sea of positive charge with electrons distributed uniformly throughout the atom (REFER TO DIAGRAM).
What force holds the atomic nucleus together? (fucking shitly worded lock in on answer)
The atomic nucleus is made up of densely packed protons and neutrons that are held together by strong attractive nuclear forces
What did Rutherford’s gold foil experiment reveal about atomic structure, and how did he discover it?
Atoms have a dense, positively charged nucleus. Rutherford discovered this by bombarding gold foil with alpha particles—most passed through, but some deflected sharply, proving the nucleus exists.
What is the strong nuclear force?
It’s the force that holds protons and neutrons together in the nucleus, overcoming Coulomb repulsion. It acts at a very short range (~1 fm).
How is nuclear stability determined?
Nuclear stability depends on the strong nuclear force (which holds nucleons together), electrostatic repulsion (between protons), and the neutron-to-proton (N/Z) ratio. A balanced N/Z ratio keeps the nucleus stable.
Why do protons in the nucleus repel each other (coulomb’s law)?
Protons in the nucleus repel each other because they have the same positive charge. According to Coulomb’s Law, like charges exert a repulsive electrostatic force on each other, which increases as they get closer. This repulsion is counteracted by the strong nuclear force, which holds the nucleus together.
Refer to nucleur stability graph and understand - notes:
Beta-minus (β⁻) decay: Occurs above the stability line (too many neutrons). A neutron converts into a proton, emitting an electron. Moves the nucleus down and right.
Beta-plus (β⁺) decay: Occurs below the stability line (too many protons). A proton converts into a neutron, emitting a positron. Moves the nucleus up and left.
Alpha (α) decay: Occurs far right (very large nuclei, Z > 83). The nucleus loses 2 protons and 2 neutrons, emitting an alpha particle. Moves the nucleus down and left.
What is half life and how is measured?
Half-life (T₁/₂) is the time it takes for half of the radioactive isotopes in a sample to decay into a more stable form by emitting alpha, beta, or gamma radiation.
𝑁= 𝑁o(1/2)n
N = Final amount of the substance remaining.
N0= Initial amount of the substance.
𝑛= Number of half-lives that have passed.
n=totaltime/half-lifetime
