Why was Rutherford's model of the atom known as the planetary model?
Rutherford used existing ideas about the atom and proposed an atomic model in which the electrons move around the nucleus like the planets move around the sun.
RED. What did Bohr assume about the motion of electrons?
Bohr proposed that electrons traveled in circular paths around the nucleus.
RED. What is the significance of the boundary of an electron cloud?
An electron is found 90% of the time inside this boundary.
What is an atomic orbital?
a mathematical expression describing the probability of finding an electron at various locations; usually represented by the region of space around the nucleus where there is a high probability of finding an electrons
RED. How many orbitals are in the 2p sublevel?
...
RED. How many sublevels are contained in each of these principal energy levels?
a. n = 1 b. n = 2
c. n = 3 d. n = 4
a. 1 (1s)
b. 2 (2s, 2p)
c. 3 (3s, 3p, 3d)
d. 4 (4s, 4p, 4d, 4f)
RED. What are the three rules that govern the filling of atomic orbitals by electrons?
...
RED. Arrange the following sublevels in order of increasing energy: 3d, 2s, 4s, 3p.
2s, 3p, 4s, 3d
RED. Which of these orbital designations are invalid?
a. 4s
b. 2d
c. 3f
d. 3p
a. valid
b. invalid
c. invalid
d. valid
RED. What is meant by 3p3?
...
Write electron configurations for the elements that are identified by these atomic numbers:
a. 7
b. 9
c. 12
d. 36
a. 1s2 2s2 2p3; b. 1s2 2s2 2p5; c. 1s2 2s2 2p6 3s2; d. 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6
Give electron configurations for atoms of these elements:
a. Na
b. K
c. I
d. Ne
a. 1s2 2s2 2p6 3s1
b. 1s2 2s2 2p6 3s2 3p6 4s1
c. 1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p6 5s2 4d10 5p5
d. 1s2 2s2 2p6
RED. How many electrons are in the highest occupied energy level of these atoms?
a. barium
b. aluminum
c. sodium
d. oxygen
a. 2
b. 3
c. 1
d. 6
How many electrons are in the second energy level of an atom of each element?
a. chlorine
b. phosphorus
c. potassium
a. 2; b. 2; 2
RED. Write electron configurations for atoms of these elements:
a. selenium
b. titanium
c. vanadium
d. calcium
a. 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p4
b. 1s2 2s2 2p6 3s2 3p6 3d2 4s2
c. 1s2 2s2 2p6 3s2 3p6 3d3 4s2
d. 1s2 2s2 2p6 3s2 3p6 4s2
What is meant by the frequency of a wave? What are the units of frequency? Describe the relationship between frequency and wavelength.
The frequency of a wave is the number of cycles to pass a given point per unit of time. The units of frequency are hertz. The relationship between frequency and wavelength is equals the speed of light.
RED. Consider the following regions of the electromagnetic spectrum: (i) ultraviolet, (ii) X-ray, (iii) visible, (iv) infrared, (v) radio wave, (vi) microwave.
a. Use the diagram of the electromagnetic spectrum to arrange them in order of decreasing wavel
a. v, vi, iv, iii, i, ii
b. It is the reverse
List the colors of the visible spectrum in order of increasing wavelength.
red, orange, yellow, green, blue, violet
How did Planck influence the development of modern atomic theory?
scientists began to use it to explain many experimental observations that could not be explained by classical physics.
RED. Explain the difference between a photon and a quantum
A quantum is a discrete amount of energy. Photons are light quanta.
RED. What has more energy, a photon of infrared light or a photon of ultraviolet light?
A photon of ultraviolet light has a higher frequency (smaller wavelength) than a photon of infrared light. Therefore, a photon of ultraviolet light has more energy than a photon of infrared light.
RED. Explain the difference between the energy lost or gained by an atom according to the laws of classical physics and according to the quantum model of the atom.
Classical physics views energy changes as continuous. In the quantum concept, energy changes occur in tiny discrete units called quanta.
RED. "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.