Units 16-17 Flashcards
What were the two questions that the Bohr model did not answer?
- Why were there special orbits?
- Why didn’t the electrons radiate when they were in these orbits?
Which model addresses the questions in the Bohr model?
Quantum model
What kind of waves do electrons moving around an atom set up?
Standing waves
True or False: 3D standing waves have nodes and antinodes
True
What does the amplitude of the standing wave of an electron to nucleus relationship represent?
The likelihood of finding an electron at that location.
When is the probability the highest to find an electron, a node or anti-node?
Anti-node
What is the probability of finding an electron in a node?
Zero
True or False: Since the standing wave pattern is stationary (within an atom) the probability of locating electrons at any given location doesn’t change with time
True
Why don’t electrons radiate in the quantum model?
Because they are confined to a static space, which means they are not accelerating around in an orbit. If they’re not accelerating, they’re not radiating.
How do electrons move?
In an orbital
Standing waves of probability
True or False: Electrons move in an orbit around a nucleus of an atom.
FALSE
What is an orbital?
A standing wave giving the probability of finding an electron in various locations around the nucleus of an atom.
Not an orbit, just an “orbital” space where an electron COULD be found inside an atom.
True or False: Electrons orbit the nucleus of an atom like planets orbit a star
False
True or False: There are different shapes of orbitals
True
What determines the shape of the orbital?
The number of standing waves and how those waves extend to space.
What are spherical harmonics?
The standard shapes of the orbitals
True or False: An electron in an atom has a fixed wavelength.
True
How does the quantum model explain why orbitals are discrete?
Because fixed wavelengths can only be set up (to create standing waves) at the exact right distance from the nucleus.
Imagine the string being shaken to create standing waves. They can only be created if they are WHOLE integers and the exact right distance apart to create nodes and anti-nodes.
What is spectroscopy?
The study of the brightness and wavelengths of the different frequencies of light emitted by excited atoms and ions.
True or False: The electron can be found inside the nucleus of an atom.
TRUE
But it’s extremely unlikely given the sizes.
How many types of orbitals are in the “p” orbital set?
3
Oriented on x, y, and z axis
What gives shape to atoms and molecules?
The directionality and orientation (cardinal points) of the lobes of an orbital
How many kinds of “d” orbitals are there?
5 total
4, four leaf clovers
1 dumbell with a donut
True or False: The Quantum model can also apply to the nucleus of an atom
True
What characteristics are the same within orbitals of the same type?
General form
What characteristics are DIFFERENT within orbitals of the same type?
Size, energy, radial shape
What is radial shape?
The cross section of an orbital that has been sliced through the center.
What is a shell?
A group of orbitals having similar energies and sizes.
True or False: Electrons in higher-numbered orbitals are more likely to be found farther from the nucleus.
True
True or False: Higher numbered orbitals also possess more energy than lower numbered orbitals of the same type
TRUE
Why do orbitals farther away have greater electrical potential energy?
Because the electrons are farther away from the protons. (opposite charges)
How many characteristics does an electron orbital have in an atom?
- Shape
- Shell
- Spin
What is spin in the context of electrons and orbitals?
The direction of the electron’s magnetic field.
It is NOT an electron spinning within an orbital.
True or False: Electrons have magnetic fields
True
How many directions can the spin of an electron be in?
2
Up and down
What is an eV?
Electron volt
A small amount of energy used to measure energies of particles in atoms.
What does the quantum model say about the movement of electrons within their orbitals?
That the places where they’re found doesn’t change with time. So the electrons are not moving or accelerating (and therefore, not radiating)
True or False: There’s a limit to how many waves can pass through a single point at one time.
False
True or False: Due to an electron’s wave nature, an infinite number of electrons can occupy the same orbital.
False
What is the exclusion principle?
The rule that two electrons cannot be in exactly the same state in an atom.
In other words, no two electrons in the same atom can have exactly the same shell, orbital, and spin values.
True or False: The exclusion principle says that even when two electrons have a probability of being in the same place at the same time, they cannot be in the same state.
True