Chemistry Chapter 5 Test
The energy of electrons in atoms are said to be quantized. Explain what this means.
The amount of energy an electron took to move from one energy level to another.
What happens when a hydrogen atom absorbs a quantum of energy?
The electron of the Hydrogen atom is raised (excited) to a higher energy level.
How is the change in electron energy related to the light emitted from the atom?
The light emitted by an electron moving from a higher to a lower energy level has a frequency directly proportional to the energy change in the electron.
What are 3 rules for writing electron configurations of elements?
aufbau principle, pauli exclusion principle, and hund's rule
What are units of frequency?
hertz
What is meant by the frequency of a wave?
how many complete cycles per unit of time.
Quantum mechanics describes the...
motions of subatomic particles and atoms as waves
Rutherford's planetary model could not explain...
the chemical properties of elements
Sketch 1s,2s,and 2p orbitals using the same scale for each.
1s- orbital is spherical 2s- orbital is spherical with a diameter larger than that of the 1s orbital 2p- orbitals are dumbbell shaped and oriented at right angles to each other.
Why does one electron in a potassium atom go into the fourth energy level instead of squeezing into the third energy level along with the eight already there?
Because the third shell is full, the rule of quantum mechanics prevent the third level from holding more than eight electrons.
What was the basic proposal in the Bohr model of the atom?
Bohr proposed that an electron is found only in specific circular paths, or orbits, around the nucleus.
How does quantum mechanics differ from classical mechanics?
Classical mechanics adequately describes the motions of bodies much larger than atoms while quantum mechanics describes the motions of subatomic particles and atoms as waves.
How do two sublevels of the same principal energy level differ from each other?
Each energy sublevel corresponds to an orbital of different shape describing where the electron is likely to be found.
How can electrons in an atom move from one energy level to another?
It changes when it obsorbs or emits light
Explain the difference between an orbit in the bohr model and an orbital in the quantum mechanical model of the atom.
Orbi in Bohr's model are specific circular paths, while an orbital in the quantum mechanical model has electron clouds that have a 90% of finding an electron.
Describe Rutherfords model of the atom and compare it to the model of his student Niels Bohr.
Rutherford suggested the atom had a dense positively charged nucleus which occupied little space and that there was much empty space in the atom where the elctrons floated in a circle around the nucleus///Bohr suggested that there were rings which each held a specific amout of electrons and were held together by the force of attraction
What did Bohr assume about about the motion of electrons?
That electrons traveled in circular paths around the nucleus.
What does the quantum mechanical model determine about electrons in atoms?
The quantum mechanical model determines the allowed energies an electron can have and how likely it is to find the electron in various locations around the nucleus.
Describe the relationship between frequency and wavelength
The wavelength and frequency of light are closely related. The higher the frequency, the shorter the wavelength. Because all light waves move through a vacuum at the same speed, the number of wave crests passing by a given point in one second depends on the wavelength.
What causes the atomic emission spectrum of an element?
When atoms absorb energy electrons move into higher energy levels and these electrons lose energy by emitting light when they return to lower energy levels.
The quantum mechanical model determines the...
allowed energies an electron can have and how likely it is to be found in various locations around the nucleus
To explain the photoelectric effect, Einstein said that light could...
be described as quanta of energy that behave as particles
When atoms absorb energy, electrons move into higher energy levels, and then lose...
energy by emitting light when the electrons drop back to lower energy levels.
The wavelength and frequency of light are...
inversely proportional to each other
Bohr proposed that electrons move...
only in specific circular paths, or orbits, around the nucleus at fixed energy levels
Classical mechanics describes...
the motions of bodies much larger than atoms
Each sub level of a principle energy level corresponds...
to an orbital shape describing where the electron is likely to be found
The light emitted by an electron moving from a higher to a lower energy level is equal...
to the energy absorbed by the electron
