Chemistry Chapter 5 Study Guide
You use a microwave oven to heat your dinner. The frequency of the radiation is 2.37 109 s−1. What is the energy of one photon of this radiation?
1.57 x 10^-25 J
Write the electron configurations of Hydrogen, Helium, Lithium, Beryllium, and Boron?
1s^1 1s^2 1s^2 2s^1 1s^2 2s^2 1s^2 2s^2 2p^1
Write the electron configurations of Carbon, Nitrogen, Oxygen, Fluorine, and Neon?
1s^2 2s^2 2p^2 1s^2 2s^2 2p^3 1s^2 2s^2 2p^4 1s^2 2s^2 2p^5 1s^2 2s^2 2p^6
An atom of an element has two electrons in the first energy level and five electrons in the second energy level. Write the electron configuration for this atom and name the element. How many unpaired electrons does an atom of this element have?
1s^2 2s^2 2p^3 Nitrogen (7 electrons) Three unpaired electron in the 2p sublevel
What are the electron configurations of Sodium, Magnesium, Aluminum, Silicon, and Phosphorus?
1s^2 2s^2 2p^6 3s^1 1s^2 2s^2 2p^6 3s^2 1s^2 2s^2 2p^6 3s^2 3p^1 1s^2 2s^2 2p^6 3s^2 3p^2 1s^2 2s^2 2p^6 3s^2 3p^3
Write the electron configurations of Sulfur, Chlorine, Argon, Potassium, and Calcium?
1s^2 2s^2 2p^6 3s^2 3p^4 1s^2 2s^2 2p^6 3s^2 3p^5 1s^2 2s^2 2p^6 3s^2 3p^6 1s^2 2s^2 2p^6 3s^2 3p^6 4s^1 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2
What is element 25, its abbreviation, and what is its electron configuration?
Manganese; Mn; 1s^2 2s^2 2p^6 3s^2 3p^6 3d^5 4s^2
Describe how the wavelength of a wave changes if the frequency of the wave is multiplied by 1.5.
The wavelength will be ⅔ the original wavelength of the wave
What is the energy of a photon of green light with a frequency of 5.80 1014 /s?
(6.626 x 10^-34 js)(5.80 x 10^14 /s) energy=h x (v/ frequency) Energy= 3.84 x 10^-19 J
c=
(weird symbol that looks like an upside-down y)*v
Write the electron configuration for an arsenic atom. Calculate the total number of electrons in each energy level and state which energy levels are not full.
1s^2 2s^2 2p^6 3s^2 3p^6 3d^10 4s^2 4p^3 n=1: 2 electrons, n=2: 8 electrons, n=3: 18 electrons, and n=4: 5 electrons 4th energy level because 4p^3 isn't full.
Suppose your favorite AM radio station broadcasts at a frequency of 1150 kHz. What is the wavelength, in centimeters, of the radiation from the station?
2.998 x 10^8 m/s x 10^2=2.998 x 10^10 cm/s [(constant in centimeters)2.998 x 10^10 cm/s] /[(frequency)1150000 s]= wavelength=26069.6 cm
Arrange the following sublevels in order of increasing energy: 3d, 2s, 4s, 3p.
2s, 3p, 4s, 3d
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. Thus, a photon of ultraviolet light has more energy than a photon of infrared light.
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 wavelength. b. How does this order differ from that of decreasing frequency?
A. (v) radio wave, (vi) microwave, (iv) infrared, (iii) visible, (i) ultraviolet, (ii) X-ray B. The two orders differ because the shorter the wavelength is, the higher the frequency is. Thus, the order for frequency would be the exact opposite.
Calculate the following energies: a. One photon of infrared radiation, if = 1.2 10−4 m. b. One photon of visible radiation, if = 5.1 10−7 m. c. One photon of ultraviolet radiation, if = 1.4 10−8 m. What do the answers indicate about the relationship between the energy of light and its wavelength?
A. 1.66 x 10^-21 J B. 3.90 x 10^-19 J C. 1.7 x 10^-17 J The shorter the wavelength, the higher the energy of the photon of light.
How many electrons are in the second energy level of an atom of each element? a. chlorine b. phosphorus c. potassium
A. 17 B. 13 C. 19
Write electron configurations for the elements that are identified by these atomic numbers: a. 7 b. 9 c. 12 d. 36
A. 1s^2 2s^2 2p^3 B. 1s^2 2s^2 2p^5 C. 1s^2 2s^2 2p^6 3s^2 D. 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6
Give electron configurations for atoms of these elements: a. Na b. K c. I d. Ne
A. 1s^2 2s^2 2p^6 3s^1 B. 1s^2 2s^2 2p^6 3s^2 3p^6 4s^1 C. 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2 3d^10 4p^6 5s^2 4d^10 5p^5 D. 1s^2 2s^2 2p^6
Write electron configurations for atoms of these elements: a. selenium b. titanium c. vanadium d. calcium
A. 1s^2 2s^2 2p^6 3s^2 3p^6 3d^10 4s^2 4p^4 B. 1s^2 2s^2 2p^6 3s^2 3p^6 3d^2 4s^2 C. 1s^2 2s^2 2p^6 3s^2 3p^6 3d^3 4s^2 D. 1s^2 2s^2 2p^6 3s^2 3p^6 4s^2
What is the maximum number of electrons that can go into each of the following sublevels? a. 2s b. 4s c. 4p d. 4f e. 3p f. 3d g. 5s h. 5p
A. 2 B. 2 C. 6 D. 14 E. 6 F. 10 G. 2 H. 6
How many electrons are in the highest occupied energy level of these atoms? a. barium b. aluminum c. sodium d. oxygen
A. 2 electrons B. 3 electron C. 1 electron D. 6 electrons
A mercury lamp, such as the one below, emits radiation with a wavelength of 4.36 10−7 m. a. What is the wavelength of this radiation in centimeters? b. In what region of the electromagnetic spectrum is this radiation? c. Calculate the frequency of this radiation.
A. 4.36 x 10^−5 cm B. Visible C. 6.88 x 10^14/s
Give the symbol for the atom that corresponds to each electron configuration. a. 1s22s22p63s23p6 b. 1s22s22p63s23p63d104s24p64d75s1 c. 1s22s22p63s23p63d104s24p64d104f75s25p65d16s2
A. Argon B. Ruthenium C. Europium
What will happen if the following occur? a. Monochromatic light shining on cesium metal is just above the threshold frequency. b. The intensity of the light increases, but the frequency remains the same. c. Monochromatic light of a shorter wavelength is used
A. Electrons of a low velocity will be emitted. The electrons will be ejected with the same amount of energy as that of the light. B. More electrons will be emitted, but with the same low velocity C. Electrons will be emitted with a higher velocity.
Indicate whether each of the following electron transitions emits energy or requires the absorption of energy. a. 3p to 3s b. 3p to 4p c. 2s to 2p d. 1s to 2s
A. Emits B. requires the absorption of energy C. requires the absorption of energy D. requires the absorption of energy
Apply Concepts Identify the elements whose electrically neutral atoms have the following electron configurations. a. 1s22s22p5 b. 1s22s22p63s23p63d104s24p2 c. 1s22s22p63s23p63d34s2
A. Fluorine B. Germanium C. Vanadium
Sodium vapor lamps are used to illuminate streets and highways. The very bright light emitted by these lamps is actually due to two closely spaced emission lines in the visible region of the electromagnetic spectrum. One of these lines has a wavelength of 5.890 10−7 m, and the other line has a wavelength of 5.896 10−7 m. a. What are the wavelengths of these radiations in centimeters? b. Calculate the frequencies of these radiations. c. In what region of the visible spectrum do these lines appear?
A. Line 1: 5.890 x 10^−5 cm Line 2: 5.896 x 10^−5 cm B. (2.998 x 10^6 cm/s)/wavelength=frequency Line 1: 1.964 x 10^1 cm Line 2: 1.966 x 10^1 cm C. green-yellow region?
How many paired electrons are there in an atom of each element? a. helium b. sodium c. boron d. Oxygen
A. One B. Five C. Two D. Five
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. One sublevel: 1s. B. Two sublevels: 2s and 2p. C. Three sublevels: 3s, 3p, and 3d. D. Four sublevels: 4s, 4p, 4d, and 4f
Give the symbols and names of the elements that correspond to these configurations of an atom. a. 1s22s22p63s1 b. 1s22s22p3 c. 1s22s22p63s23p2 d. 1s22s22p4 e. 1s22s22p63s23p64s1 f. 1s22s22p63s23p63d24s2
A. Sodium, Na (11 electrons) B. Nitrogen, N (7 electrons) C. Silicon, Si (14 electrons) D. Oxygen, O (8 electrons) E. Potassium, K (19 electrons) F. Titanium, Ti (22 electrons)
Infer Picture two hydrogen atoms. The electron in the first hydrogen atom is in the n = 1 level. The electron in the second atom is in the n = 4 level. a. Which atom has the ground state electron configuration? b. Which atom can emit electromagnetic radiation? c. In which atom is the electron in a larger orbital? d. Which atom has the lower energy?
A. The atom with electron in n=1 level B. The atom with electron in n=4 level because it will emit light when dropping to a lower energy level; the first one is already at the lowest energy level. C. The atom with electron in n=4 level D. The atom with electron in n=1 level
Infer Which of the following is the ground state of an atom? Which is its excited state? Which is an impossible electron configuration? Identify the element and briefly explain your choices. a. 1s22s22p63s23p65p1 b. 1s22s22p63s23p64s1 c. 1s22s22p63s23p7
A. excited state, valence electron has been promoted from 4s to 5p B. ground state, lowest energy electron configuration C. impossible configuration, 3p orbitals can hold a maximum of 6 electrons not 7
What is the significance of the boundary of an electron cloud?
An electron is found 90% of the time inside the boundary. However, there is no actual boundary to an electron cloud because there is a slight chance of the electron being a considerable distance away from the nucleus. Thus, the attempts to show probabilities as a fuzzy cloud are limited to where the electron may be 90% of the time.
What are the three rules that govern the filling of atomic orbitals by electrons?
Aufbau Principle-electrons occupy the orbitals of lowest energy first. Pauli Exclusion Principle- an atomic orbital may describe at most two electrons. Hund's Rule- electrons occupy orbitals of the same energy in a way that makes the number of electrons with the same spin direction as large as possible.
What three very important atomic rules are compared to house/hotel rules?
Aufbau, Pauli, and Hund's
Explain the difference between a photon and a quantum
Basically, a quantum is a discrete amount of energy, while photons are light quanta. A photon is a quanta of light energy that behaves as a particle. A quantum is the amount of energy needed for an electron to move from one energy level to another. A quantum is a discrete bundle of energy. It can be delivered by a photon. A quantum leap in an atom is when a photon carrying just the right amount of energy is absorbed by the atom and its electron jumps to a higher quantum level or higher orbital.
What is element 24, its abbreviation, and what is its electron configuration?
Chromium; Cr; 1s^2 2s^2 2p^6 3s^2 3p^6 3d^5 4s^1
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.
What is element 27, its abbreviation, and what is its electron configuration?
Cobalt; Co; 1s^2 2s^2 2p^6 3s^2 3p^6 3d^7 4s^2
What is element 29, its abbreviation, and what is its electron configuration?
Copper; Cu; 1s^2 2s^2 2p^6 3s^2 3p^6 3d^10 4s^1
Relate Cause and Effect Why do electrons occupy equal energy orbitals singly before beginning to pair up?
Electrons occupy orbitals of the same energy in a way that makes the number of electrons with the same spin directions as large as possible. Electrons then occupy each orbital so that their spins are paired with the first electrons in the orbital, after each orbital has one electron each.
What did Bohr assume about the motion of electrons?
His main proposal was that electrons traveled in circular paths around the nucleus. His model assumed that the electrons of an atom are found in specific orbitals around the nucleus, having fixed energy levels. The electrons can't exist between energy levels, but can move to different energy levels with the right quanta of energy.
State the Heisenberg uncertainty principle.
It is impossible to know both the velocity and the position of a particle at the same time.
What is element 28, its abbreviation, and what is its electron configuration?
Nickel; Ni; 1s^2 2s^2 2p^6 3s^2 3p^6 3d^8 4s^2
Predict Traditional cooking methods make use of infrared radiation (heat). Microwave radiation cooks food faster. Could radio waves be used for cooking? Explain.
Radio waves have the lowest energy in the electromagnetic spectrum and, thus, it wouldn't be energetic enough to cook food. Also, if microwaves cook food faster than infrared radiation, than radio waves would cook food even faster.
List the colors of the visible spectrum in order of increasing wavelength.
Red, orange, yellow, green, blue, and violet.
Main orbital shapes
Remember that they can be arranged in different positions (sphere, dumbell, clover, and complicated shape)
Describe Rutherford's model of the atom and compare it with the model proposed by his student Niels Bohr.
Rutherford's model of the atom described negatively-charged electron particles freely/randomly moving around the nucleus, which contained positively-charged protons and neutrally-charged neutrons. Bohr's model proposed that electrons are found only in specific orbits around the nucleus, these orbits having fixed energy levels. The electrons must gain or lose just the right quantum of energy to move from one energy level to another. These energy levels are not equally spaced, and the amount of energy an electron gains or loses isn't always the same either. The higher the energy level, the closer the energy levels are to each other.
What is the main difference of Rutherford's model and Bohr's model?
Rutherford= had electrons randomly circling the nucleus Bohr= specific distance and orbits of electrons
What are the four energy levels?
S, P, D, and F
What is element 21, its abbreviation, and what is its electron configuration?
Scandium; Sc; 1s^2 2s^2 2p^6 3s^2 3p^6 3d^1 4s^2
What mathematical equation founded the quantum mechanical model?
Schrodingr's equation
Evaluate and Revise Orbital diagrams for the ground states of two elements are shown below. Each diagram shows something that is incorrect. Identify the error in each diagram and then draw the correct diagram. a. Nitrogen b. Magnesium
Sorry, figure it out on your own
Compare Explain the difference between an orbit in the Bohr model and an orbital in the quantum mechanical model of the atom.
The Bohr model said that electrons could only be found on specific orbits. Each orbit would have a fixed energy level. The electrons could transition to the different energy levels by gaining or losing enough energy. Unlike the Bohr model, the quantum mechanical model does not specify an exact path that an electron must take around the nucleus. This model's orbitals are described as the probability of finding electrons at various locations around the nucleus.
Why was Rutherford's model of the atom known as the planetary model?
The atomic model that Rutherford proposed was called the planetary model because it showed the electrons moving around the nucleus like the planets orbit the Sun.
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 represents the number of wave cycles that pass a given point per unit of time. The SI basic unit of cycles per second for frequency is Hertz, which can be expressed as a reciprocal second (s^-1). The wavelength (represented by the upside down y) is the distance between the crests of a wave. The frequency (represented by v), however, is the number of wave cycles to pass a given point per unit of time. The product of wavelength and frequency is the constant ( c) speed of light.
What happens when a hydrogen atom absorbs a quantum of energy?
The hydrogen atom's electron would raise (or excite) to a higher energy level, when the atom absorbs a quantum of energy. The electron loses energy by emitting light when it returns to a lower energy level.
White light is viewed in a spectroscope after passing through sodium vapor too cool to emit light. The spectrum is continuous except for a dark line at 589 nm. How can you explain this observation? (Hint: Recall from Sample Problem 5.2 that the atomic emission spectrum of sodium exhibits a strong yellow line at 589 nm.)
The outermost electron of sodium absorbs photons of wavelength 589 nm as it jumps to a higher energy level, but the electron is not energetic enough to emit a photon at this wavelength. Thus, the white light spectrum exhibits a dark line at 589 nm.
What is meant by 3p3?
The p orbitals in the third quantum level have three electrons. The first "3" represents the principal energy level. The "p" represents the type of orbital. The second "3" refers to the number of electrons in that sublevel. This altogether is meant to describe the location of electron(s) at a certain energy level and sublevel.
Draw Conclusions Think about the currently accepted models of the atom and of light. In what ways do these models seem strange to you? Why are these models not exact or definite?
This is your own opinion mostly
How many orbitals are in the 2p sublevel?
Three orbitals: 2px, 2py, and 2pz
What is element 22, its abbreviation, and what is its electron configuration?
Titanium; Ti; 1s^2 2s^2 2p^6 3s^2 3p^6 3d^2 4s^2
What is the maximum number of electrons that can be found in any orbital of an atom?
Two electrons per orbital
What is element 23, its abbreviation, and what is its electron configuration?
Vanadium; V; 1s^2 2s^2 2p^6 3s^2 3p^6 3d^3 4s^2
How did Planck influence the development of modern atomic theory?
With Planck's constant (E=hv), which shows that the amount of radiant energy (E) of a single quantum absorbed or emitted by a body is proportional to the frequency of radiation (v), many scientist began to use it to explain many experimental observations that couldn't be explained by classical physics. Einstein also used his theory/constant to explain the photoelectric effect, which also couldn't be explained by classical physics that said under even weak light of any wavelength, an electron in a metal should eventually collect enough energy to be ejected. Einstein realized that light behaves both as waves and particles (photons), and that there's a minimal threshold value of energy of the photoelectric effect. With this idea that light, originally thought as a wave of energy, has particle properties also, opened up the idea that matter (like electrons and atoms) could have wave-like properties. Thsu, bringing about the use of using wavelengths, frequencies, and etc. to identify elements.
What is element 30, its abbreviation, and what is its electron configuration?
Zinc; Zn; 1s^2 2s^2 2p^6 3s^2 3p^6 3d^10 4s^2
Define 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's a high probability of finding an electron
Define Planck's Constant
a number used to calculate the radiant energy (E) absorbed or emitted by a body based on the frequency of radiation
Define spin
a quantum mechanical property of electrons that may be thought of as clockwise of counterclockwise
Define photon
a quantum of light; a discrete bundle of electromagnetic energy that intersects with matter simiiarly to particles
What is an atomic orbital?
an atomic orbital is a mathematical expression describing the possibility 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 electron.
Define Pauli Exclusion principle
an atomic orbital may describe at most two electrons, each with opposite spin directon
On the atomic level, how do fireworks work?
atoms are heated up and electrons go to higher orbitals. Light is emitted after the atoms cool and go down orbitals.
Which of these orbital designations are invalid? a. 4s b. 2d c. 3f d. 3p
b and c
How do these electrons lose energy?
by emitting light when they return to lower energy levels
How were all atomic models developed?
by experiments/observations, except for the quantum mechanical model which was based on mathematical equations
How can electrons move from one energy level to the next?
by gaining or losing just the right amount of energy
How does Einstein explain the photoelectric effect?
by proposing that light could be described as quanta of energy that behave as if they were particles
What two elements have an exception in doing normal electron configurations?
copper and chromium
What were some of the inadequacies of Rutherford's model?
electrons lose energy, would implode because atoms have opposite charges, and would emit light while spiraling
Define Hund's rule
electrons occupy orbitals of the same energy in a way that makes the number of electrons with the same spin direction as large as possible
How can energy be compared to a TV screen?
energy appears continuous, but when zoomed in, there are pixels or quanta of energy
Define electromagnetic radiation
energy waves that travel in a vacuum at a speed of 2.998 x 10^8 m/s; includes radio waves, microwaves, inftared waves, visible light, ultraviolet waves, X-rays, and gamma rays
E=
hv
What atom did Niels Bohr study and what discoveries did he incorporate into his new atomic model?
hydrogen because it's the simplest; how an atom's energy changes when the atom absorbs or emits light
What is element 26, its abbreviation, and what is its electron configuration?
iron; Fe 1s^2 2s^2 2p^6 3s^2 3p^6 3d^6 4s^2
Describe the light emitted by an electron moving from a higher to a lower energy level
it has a frequency directly proportional to the energy change of the electron
Describe the general energy of electrons
lot of energy, very fast. They move even at absolute zero
Each energy sublevel corresponds to what?
one or more orbitals of different shapes
What does each character in 1s^1 stand for?
one=energy level, s=orbital, one= electron(s)
Define Heisenberg Uncertainty
pairs of observable physical properties correspond to noncommuning quantum mechanical variables can't be simultaneously determined. In particular, the minimum of the product of the uncertainties in these properties that's equal or greater than h/2, where h is the reduced Planck's Constant
What do you need to keep in mind when doing electron configurations?
stableness and symmetry are always best
What did Bohr propose?
that an electron is found only in specific circular paths, or orbits, around the nucleus
What does the quantum mechanical model determine?
the allowed energies an electron can have and how likely it is to find the electron in various locations around the nucleus of an atom
Define quantum
the amount of energy needed to move an electron from one energy level to antother
Define electron configuration
the arrangement of electrons of an atom in its ground state into various orbitals around the nuclei of atoms
What are the 3 rules that tell you how to find the electron configuration of atoms?
the aufbau principle, the Pauli exclusion principle, and Hund's rule
Rutherford's atomic model of electrons orbiting the nucleus was simple, and failed to explain...
the chemical properties of elements, why metals or compounds of metals give off characteristic colors when heated in a flame, why an object (such as an iron scroll) first glows dull red then yellow and then white when heated to higher temp.
Define wavelenght
the distance between adjacent crests of a wave
Define photoelectric effect
the ejection of electrons by certain metals when they absorb light with a frequency above a threshold frequency
Define amplitude
the height of a wave's crest
Define ground state
the lowest possible energy of quantum described by quantum mechanics
Define Quantum Mechanical Model
the modern description, primarily mathematical, of the behavior of electrons in atoms
What does Classical Mechanics adequately describe?
the motions of bodies much larger than atoms
What does Quantum Mechanics describe?
the motions of subatomic particles and atoms as waves
Define frequency
the number of wave cycles that pass a given point per unit of time; this and wavelength are inversely proportional to each other
Define Atomic Emission Spectrum
the pattern formed when light passes through a prism of diffraction grating to separate it into the different frequencies of light it conatins
In the Periodic Table, what do the energy levels correspond to?
the periods
Define Aufbau principle
the rule that electrons occupy the orbitals of lowest energy first
What can you compare energy levels of an atom to?
the rungs of a ladder; the farther the rungs are from the nucleus, though, the closer they are to each other
Define Energy Level
the specific energies an electron in an atom or oher system can have
Define Hertz
the unit of frequency, equal to one cycle per second
What happens when atoms absorb energy?
their electrons move to higher energy levels
Describe the energy levels of metaloids
they are very close
Describe atoms at absolute zero
they're at their state of least motion
Calculate the energy of a photon of red light with a wavelength of 6.45 10−5 cm. Compare your answer with the answer to Question 52. Is red light of higher or lower energy than green light?
v=(2.998 x 10^8 m/s)/6.45 x 10^-7 cm) x 10^2 cm= 4.65 x 10^14/s E=(6.626 x 10^-34 Js) x (4.65 x 10^14/s)= 3.08 x 10^-19 J Red light photon energy= 3.08 x 10^-19 J Red light is lower energy than green light
Define Spectrum
wavelenghts of visible light that are separated when a beam of light passes through a prism; range of wavelengths of electromagnetic radiation
What does the orbitals describe?
where an electron is likely to be found
Describe your hypothetical atomic house
you are an electron, your house is an atom, the stories are orbitals, and the rooms are sublevels