Chapter 13 Test Flashcards
Who was John Dalton?
Developed the first atomic theory; atom is a solid, neutral sphere
Who was JJ Thomson?
Discovered electrons; an atom is a solid, neutral sphere with embedded electrons.
Describe Thomson’s experiment.
He used a cathode tube with the rays bending at the negatively charged plates so he could tell they were negatively charged
Who was Ernest Rutherford?
Discovered nucleus with the gold foil experiment
Describe the gold foil experiment.
He had gold foil in between a red box and a detector. He noticed that 99.9% of alpha particles went straight through the foil to the detector. This was the first nuclear atomic model.
What were Rutherford’s conclusions from the gold foil experiment?
- Atoms are made of empty space
- There must be a small, dense, positive charge in atoms (the nucleus)
Who was Niels Bohr and what did he do?
Created the Planetary Model. Electrons travel in circular paths around the nucleus in their ground state. He stated that electrons have a minimal amount of energy that keeps them in orbit (ground state)
What is ground state?
The lowest, most stable energy state of an electron. Electrons do not go below ground state.
What is excited state?
Higher, less stable energy state of an electron
What is the Quantum Mechanical Model?
The modern stomic model/theory that describes the electronic structure of the atom as the probability of finding electrons within certain regions of space.
What can happen with electrons in the Quantum Mechanical Model?
They can move from one energy level to another. From stable states, they can gain energy from ground to excited states. They can go to a higher energy level and use more energy.
When is light produced?
When electrons gain normal, specific amount of energy called a quantum.
What happens when electrons gain quantums?
They leap from their ground state to their excited state. In their excited state, electrons are unstable and want to return to their ground state. To do this, the electrons must lose the same quantum of energy they gained. They lose this energy in the form of light and/or heat.
What happens when energy is released after it is lost in the quantum mechanical model?
Once the energy is released, the electrons return to ground state.
How many quantum numbers are there?
4
Compare incandescent bulbs and fluorescent bulbs.
In incandescents, electrons give lots of energy at excited state, which is very unstable so it not as efficient. Fluorescents use less energy because the gas is spread at a ground state, so they are more efficient when lighting large areas.
What equation is the Quatnum Model based on?
Schrodinger equation
What are the four quantum numbers?
Energy Levels, Subshells, Oribtals, Spins
What is the symbol for the energy level?
n
What is the symbol for the subshell?
L
What is the symbol for the orbital?
m
What is the symbol for the spins?
s
How many energy levels are there?
7
How many electrons can be held in each energy level?
1st-2 2nd-8 3rd-18 4th-32 5th-32 6th-18 7th-8