Flashcards
Atomic and Nuclear Structure
Flashcards do conjunto (28)
- 1emission spectrum of hydrogen (Bohr model)- Electrostatic attraction pulls the electron toward the nucleus.
- The electron orbits at high speed to prevent it from crashing into the nucleus.
- The electron can orbit at different energy levels: n=1, n=2, n=3 ...etc.
- The higher the energy level, the larger the radius from the nucleus. - 2emission spectrum of hydrogenWhen an electron transitions from a higher energy level to a lower energy level, it emits electromagnetic radiation.
The emission spectrum of hydrogen consists of sharp, distinct lines. - 3quantized energy levels for electronsThe distinct lines of the emission spectrum prove that electron energy is quantized into energy levels.
(If electron energy is not quantized, then a continuous spectrum would be observed.) - 4energy of the energy levels (equation for hydrogen only)E = -13.6eV/n²
(n = energy level)
Note: all energies are negative
The more negative (lower) the energy, the more stable the orbit and the harder it is to knock out the electron.
At the highest energy (0eV) there is no binding energy, so the electron dissociates. - 5energy emitted or absorbed when an electron changes energy levelsE = hf
= hc/λ - 6Atomic weightThe weighted average of atomic mass for all isotopes of a given atom. Used for an element. Seen as a superscript to the left of the element.
- 7Atomic massAtomic mass = number of protons + neutrons
Used for isotopes. - 8NucleonsProtons or neutrons
- 94 Fundamental forces- Strong/Nuclear force
- Electromagnetic force
- Weak force
- Gravity - 10Strong (Nuclear) Force- The strongest of the four fundamental forces.
- Only acts at subatomic distances.
- Binds nucleons together. - 11Electromagnetic force- ~1 order of magnitude weaker than the strong force.
- Acts at observable distances.
- Responsible for binding atoms together and magnetic attraction.
- Common MCAT example: Why you are not falling through your chair right now. - 12Weak force- ~10 orders of magnitude weaker than the strong force.
- Responsible for radioactive decay. - 13Gravity- ~50 orders of magnitude weaker than the strong force.
- Responsible for weight and planet orbits. - 14Alpha decayEjection of a helium nucleus at relatively low speed.
Mass: -4
Atomic number: -2 - 15Beta decay- Ejection of a high speed electron.
- A proton is transformed into a neutron, or vice versa.
- Allows the atom to move closer to the optimal ratio of protons and neutrons.
- Nucleus emits a detectable beta particle (electron or positron). - 16Electron emission (β− decay)Produces: electron + electron antineutrino
Mass: same
Atomic number: +1 - 17Positron emission (β+ decay)Produces: positron + electron neutrino
Mass: same
Atomic number: -1 - 18Gamma decayRelease of high energy electromagnetic wave.
- 19Alpha particle ⁴₂α- Weakest form of radiation.
- Can be stopped by a sheet of paper.
- Essentially a low speed helium nucleus. - 20Beta particle ₋₁⁰β- More energy than an alpha particle.
- Can be stopped by aluminum foil.
- A high speed electron. - 21Gamma ray ⁰₀γ- Strongest form of radiation.
- A high energy electromagnetic wave.
- Can be stopped by a thick layer of lead or concrete. - 22Half-lifeThe time it takes for the amount of something to half due to decay.
N = N₀(½)^(# of half-lives)
= N₀(½)^(t/half-life)
N₀ = N (2)^(# of half-lives)
= N (2)^(t/half-life) - 23Exponential decay
- 24Semi-log plots- Convert exponential curves into straight lines.
-The semi-log plot intercepts the x axis where the original y value is 1.
- 25Fission- The splitting of a nucleus into two.
- Uranium undergoes fission when struck by a free neutron. - 26Fusion- Two nuclei coming together.
- The Sun works by fusion
(Hydrogen fuses to form Helium). - 27Mass deficitIf the total mass before the reaction is different from the total mass after the reaction, then the difference in mass is made up for by energy.
- 28Binding energyE = mc²
- Energy that makes up for the mass deficit.
- Due to strong force.
Informações
- Descrição
- MCAT - Physics FlashCards sobre Atomic and Nuclear Structure, criado por jessicalazar em 19-10-2014.
- Criado por
- jessicalazar · out 2014
- Atualizado
- 19 fev 2016
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- 4
- Avaliação