Knowt
Chemistry Test
Mass Defect- the difference between the mass of an isotope and its mass number
Calculation of Mass Defect- add the protons and neutrons and subtract the actual mass
Binding Energy- the amount of energy required to separate a particle from a systems of particles or to disperse all the particles of the system
How to Calculate Binding Energy- BE= MD (3.00×10^8)
Binding Energy Per Nucleon- the minimum energy required to disassemble the nucleus of an atom into its constituent neutrons and protons
How to calculate BE per Nucleon- (MD(3.00×10^8)²)/the mass of the nucleus
Stable nuclei generally have even numbers of both protons and neutrons and a neutron-to-proton ratio of at least 1
Band of stability- the neutron to proton ratios of stable nuclei, the lighter elements ratio tend to be 1:1 and the heavier elements ratio tend to be 1.5:1
The higher the binding energy the more stable the isotope is
The even number of nucleons tend to be more stable, even more stable are even numbers of protons and neutrons
Iron-56 is the most stable isotope
As the number of protons increases, the ratio increases from 1 : 1 to about 1.5 : 1
Magic Numbers- the number of nucleons that represent completed energy levels in the nucleus
The heavy particles stability ratio is 1.5:1
The light particles stability ratio is 1: 1
Transmutation- changes from one thing to another
Nuclear reactions- the transmutation of elements
Alpha particles- a helium nucleus
heaviest
slowest
2 protons
2 neutrons
heavy elements
interact with matter better at a close ranges
easily stopped by a piece of paper
Happens with heavy elements
spits out a He nucleus because the original element is too unstable and just spits it out which creates a more stable nucleus
Beta Particles- a nuclear electron
break down neutron
faster
stopped by aluminium foil and clothing
no weight
negative charge
Occurs when nuclei have too many neutrons to achieve stability
Comes from a broken down neutrons
1 less proton, 1 more nutron
Positron Particles- an electron with a +1 charge
no weight
positive charge
can be stopped by aluminium or clothing
Occurs when nuclei have too many protons to achieve stability
Comes from a protron, a neutron and a positron are created
one more proton, one less neutron
Electron Capture- when an electron from the cloud enters the nucleus
larger element plus electron yields smaller element
occurs when there are too many protons to achieve stability
neutron to proton ratio are too small
1 more neutron, one less proton
Gamma rays
electromagnetic radiation
high frequency-high energy- short wave length
can only break down Gamma power by half
Gamma rays have no mass or charge
occurs when the nucleus of an atom is unstable during radioactive decay
Energy
Half life- the amount of time it takes for half of the nucleus of a substance to decay
Effects of radioactivity on Humans- nausea, vomiting, skin redness, hair loss, radiation burns, radiation sickness, and even death
Radon is a gas which is inhaled and has a 3 day half life. Radon will ride on smoke which will stay in your lungs. It then breaks down into polonium which will stay in your lungs. Alpha particles stay in your lungs, alpha particles inside are very dangerous.
Radon equations
uranium to radon to two daughters and half lives
radium to radon to polonium to astatine
Radon effects- lung tissue damage and lung cancer
Fission- a neutron slams into a larger element causing the atom to split
Fusion- joins two or more lighter atoms to create one large atom
Non-ionizing radiation- low energy
Medium Energy- causes electrons to jump to a high energy level and then drop lower, emitting the energy they are getting rid of as light, which is why radioactive materials can glow in the darn
high energy levels begin to interfere with chemical processes especially in water, leaving a insufficient molecule searching for another thing to bond to, this effects the cell membrane which causes cells to leak which can cause a disturbance of DNA
Half life equation
Amount remaining= original amount x 1/2^n
N= elapsed time/ half life
What they did and how they discover it and what was interesting about them
Becquerel decided to investigate whether there was any connection between X-rays and naturally occurring phosphorescence. When he placed uranium salts were placed near a photographic plate covered with opaque paper, the plate was discovered to be fogged. He showed that rays emitted from uranium caused gasses to ionize which differed from x-rays. From this he discovered spontaneous radioactivity
Curies
Marie coined the word radioactive to describe radium and polonium
She established mobile radiology units to treat wounded soldiers during world war I
Her work lead to new cancer treatments
Carried radon in her pockets which lead to her having leukemia which was how she passed
Nobel prize for physics for discovering radio activity in 1903
Nobel prize in Chemistry for isolating pure radium split with Becquerel
First woman to win nobel prize
First person to win two nobel prizes
She had a pet tiger
Pierre got hit by a bus
X-Rays from Roentgen
Discovery: Wilhelm Conrad Roentgen discovered X-rays in 1895 while experimenting with cathode rays.
Observation: He noticed a fluorescent screen in his laboratory glowed without being directly exposed to the cathode rays, indicating an unknown type of radiation.
Naming: He named them "X-rays" to denote their unknown nature.
Medical Impact: Roentgen's discovery revolutionized medical imaging, enabling non-invasive internal examinations and diagnostics, leading to significant advancements in modern medicine.
Study Guide: Key Concepts in Nuclear Physics and Radioactivity
Mass Defect and Binding Energy
Mass Defect: Difference between the mass of an isotope and its mass number.
Calculation: Add the number of protons and neutrons, then subtract the actual mass.
Binding Energy: Energy needed to separate particles in a system.
Calculation: BE = MD × (9.00 × 10^16).
Binding Energy Per Nucleon: Minimum energy to disassemble a nucleus.
Calculation: (MD × (3.00 × 10^8)²) / Mass of the nucleus.
Stability of Nuclei
Stable nuclei generally have even numbers of protons and neutrons, with a neutron-to-proton ratio (N/P) of at least 1.
Band of Stability: Lighter elements ~ 1:1 ratio, heavier elements ~ 1.5:1.
Magic Numbers: Specific nucleon counts indicating stable nuclei (2, 8, 20, 28, 50, 82, 126).
Iron-56 is considered the most stable isotope.
Types of Nuclear Reactions
Transmutation: Change of one element into another.
Alpha Decay: Emission of a helium nucleus; occurs in heavy elements and easily stopped by paper.
Beta Decay: Emission of a nuclear electron when a nucleus has too many neutrons; stopped by aluminum foil.
Positron Emission: Release of a positive electron when a nucleus has too many protons; can be stopped by aluminum or clothing.
Electron Capture: An electron enters the nucleus; occurs when there are excess protons.
Gamma Rays: High-frequency electromagnetic radiation emitted from unstable nuclei; has no mass or charge.
Half-Life and Radioactivity Effects
Half-Life: Time required for half of a substance's nuclei to decay.
Equation: Amount remaining = original amount × (1/2)^n, where n = elapsed time / half-life.
Effects on Humans: Nausea, vomiting, skin redness, radiation burns, and cancer. Radon affects lung tissue, leading to lung cancer.
History of Discoveries in Radioactivity
Henri Becquerel: Discovered spontaneous radioactivity through uranium's rays; linked to X-rays.
Marie Curie: Coined 'radioactivity', discovered radium, and developed mobile radiology for treating soldiers; first woman to win Nobel Prize.
Wilhelm Roentgen: Discovered X-rays, revolutionizing medical imaging.
