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Chapter 9
Electrons in Atoms and the Periodic Table

09-00-02b
Title
Alkali metals and noble gases
Caption
The noble gases are chemically inert and the alkali metals are chemically reactive. Question: Why?
Notes
The focus of Chapter 9 is the development of a theory of the atom adequate to explain the observed chemical behavior of the elements. Ultimately, the quantum-mechanical model of the atom does the job, by detailing how the atoms' electrons are organized into energy levels, sublevel, and orbitals.
Keywords
alkali metals, noble gases, electrons, quantum-mechanical model
09-01
Title
Light travels as waves
Caption
The wavelength of light (l) is defined as the distance between adjacent crests in light waves.
Notes
Students should understand that light exhibits both wave and particle properties. When the particle nature is evident, light is a collection of particles called photons.
Keywords
light, quantum-mechanical model, wavelength
09-04
Title
Visible light makes up a small portion of the electromagnetic spectrum.
Caption
The electromagnetic spectrum spans an enormous range of energies and wavelengths. The waves are sometimes called electromagnetic radiation, and they can have significant effects on living organisms and other natural systems.
Notes
The relationship between wavelength and energy is a key concept here.
Keywords
electromagnetic, spectrum, light, energy, wavelength
09-05
Title
Treating cancer with high-energy electromagnetic radiation
Caption
Here is an example of the effect of electromagnetic radiation on matter: By targeting a tumor with high-energy X-ray or gamma radiation, the tumor cells are so damaged that they cannot reproduce; the tumor eventually dies. By focusing the radiation, damage to healthy tissue is minimized.
Notes
Students might be given a research project to discover how the radiation is produced.
Keywords
electromagnetic, spectrum, light, energy, wavelength, cancer, tumor, gamma radiation, X-ray
09-09
Title
The Bohr model of the atom, showing electron orbits
Caption
In a Bohr atom, the electron is a particle that travels in specific, fixed orbits, but never in the space between orbits. This arrangement expresses energy quantization, and accounts for atomic emission spectra.
Notes
Students should understand that the electron energy is a function of the distance from the nucleus (this makes sense, because the nucleus and electrons attract, and therefore, they must take up more energy to be pulled further apart). The line spectra show the light (energy) emitted when an electron jumps from a higher orbit to a lower one.
Keywords
electromagnetic, spectrum, light, energy, wavelength, Bohr, orbit, electron
09-10
Title
A ladder quantizes distance; a Bohr atom quantizes energy
Caption
Bohr orbits are like steps in a ladder. It is possible to be on one step or another, but it is impossible to be between steps.
Notes
The analogy is limited, in that the distance between the steps is constant, from step to step, but the difference in the energy of the Bohr orbits varies by the orbit's quantum number.
Keywords
electromagnetic, spectrum, light, energy, wavelength, Bohr, orbit, electron
09-11
Title
Energy absorption and light emission in a Bohr hydrogen atom
Caption
When a hydrogen atom absorbs energy, an electron is excited to a higher energy orbit. The electron then transitions back to a lower energy orbit and emits a photon of light.
Notes
Students should understand that the electron energy is a function of the distance from the nucleus (this makes sense, because the nucleus and electrons attract, and therefore, they must take up more energy to be pulled further apart). The line spectra show the light (energy) emitted when an electron jumps from a higher orbit to a lower one.
Keywords
electromagnetic, spectrum, light, energy, wavelength, Bohr, orbit, electron, absorption, emission, excitation
09-12
Title
Visible lines in emission spectrum of a Bohr hydrogen atom
Caption
Each Bohr orbit has a distinct, fixed energy. When an electron relaxes from a high-energy orbit to a low-energy orbit, light (energy) is released. The 486 nm line corresponds to an electron relaxing from the n = 4 orbit to the n = 2 orbit. The 657 nm line of the hydrogen emission spectra corresponds to an electron relaxing from the n = 3 orbit to the n = 2 orbit.
Notes
Students might be asked to predict which wavelengths correspond to specific orbit pairs. For example, the n = 5 to n = 1 line will be at higher energy than the n = 5 to n = 4 line.
Keywords
electromagnetic, spectrum, light, energy, wavelength, Bohr, orbit, electron, absorption, emission, excitation
09-13
Title
Electron probability: a baseball analogy I
Caption
Because it behaves as a particle, a baseball follows a well-defined path as it travels from the pitcher to the catcher. Because of their wave nature, an electron's path cannot be precisely known. The best we can do is to calculate the probability of the electron following a specific path.
Notes
In the quantum-mechanical model, specific electron orbits are not appropriate: the electron's movement cannot be known that precisely. Instead, we map the probability of finding the electron at various locations outside the nucleus. The probability map is called an orbital.
Keywords
electromagnetic, spectrum, light, energy, wavelength, electron, wave, particle, probability
09-14
Title
Electron probability: a baseball analogy II
Caption
If the baseball displayed wave-particle duality, the path of the baseball could not be precisely determined. The best we could do would be to make a probability map of where a "pitched" electron will cross home plate.
Notes
In the quantum-mechanical model, specific electron orbits are not appropriate: the electron's movement cannot be known that precisely. Instead, we map the probability of finding the electron at various locations outside the nucleus. The probability map is called an orbital.
Keywords
electromagnetic, spectrum, light, energy, wavelength, electron, wave, particle, probability
09-15
Title
Quantum-mechanical energy diagram for hydrogen atom
Caption
The principal quantum numbers (n = 1, n = 2, n = 3 ) determine the energy of the hydrogen quantum-mechanical orbitals.
Notes
Like the Bohr model, the quantum-mechanical model allows only specific energies for the electron. The difference is in the way the electron exists around the nucleus: Instead of being a little "planet" orbiting the nucleus, as Bohr envisioned, the quantum-mechanical electron's location is known only through a probability map.
Keywords
energy, wavelength, electron, wave, particle, probability, quantum-mechanical, quantum number, orbital, hydrogen
09-16
Title
Probability map for an electron: a 1s orbital
Caption
The 1s orbital. The dot density is proportional to the probability of finding the electron. The greater dot density near the middle (the nucleus) represents a higher probability of finding the electron near the nucleus.
Notes
Imagine each dot representing an observation of the electron's position; all the dots together represent the observations made over time. The more dots there are in a specific location, the higher the probability of finding the electron there.
Keywords
energy, wavelength, electron, wave, particle, probability, quantum-mechanical, quantum number, orbital, hydrogen
09-17
Title
Shape representation for a 1s orbital
Caption
Shape representation of the 1s orbital. When the electron is in the 1s orbital, it is most likely found within this sphere.
Notes
The shape is a bit misleading: It looks like the electron is confined to the sphere, but it is not. The electron can be outside the sphere, but the probability is low.
Keywords
energy, wavelength, electron, wave, particle, probability, quantum-mechanical, quantum number, orbital
09-18
Title
Comparing the probability map and the shape representation
Caption
The shape representation of the 1s orbital superimposed on the dot density representation.
Notes
A few of the dots lie outside the shape representation: The electron can be outside the sphere, but the probability is low.
Keywords
energy, wavelength, electron, wave, particle, probability, quantum-mechanical, quantum number, orbital
09-19
Title
Shells are organized into subshells
Caption
The number of subshells in a given principal shell is equal to the value of n.
Notes
There is a relationship between the quantum number (n) and the number of subshells that a shell possesses. Subshells of the same type (e.g., all of the s subshells) will have similar probability maps.
Keywords
energy, electron, quantum-mechanical, quantum number, orbital, shell, subshell
09-20
Title
Comparison of 1s and 2s orbitals
Caption
The 2s orbital is similar to the 1s orbital, but larger in size.
Notes
The phrase "larger in size" really means that the maximum probability for finding the electron lies farther out from the nucleus.
Keywords
energy, electron, quantum-mechanical, quantum number, orbital, shell, subshell
09-21
Title
Probability maps of the three 2p orbitals
Caption
The three 2p orbitals are the same size and shape, but are oriented in different directions. A careful look at the orientations reveals that they are all at right angles to one another.
Notes
The three orbitals, taken together, make up the p subshell of the n = 2 shell. Each orbital can hold a maximum of two electrons.
Keywords
energy, electron, quantum-mechanical, quantum number, orbital, shell, subshell
09-22
Title
Probability maps of the five 3d orbitals
Caption
The five 3d orbitals are generally oriented in different directions. If we were to add all five orbitals, we would get a sphere.
Notes
The five orbitals, taken together, make up the d subshell of the n = 3 shell. Each orbital can hold a maximum of two electrons.
Keywords
energy, electron, quantum-mechanical, quantum number, orbital, shell, subshell
09-23
Title
A nucleus behaves like a magnet in a magnetic field
Caption
A nucleus is like a small magnet that aligns itself with an external magnetic field.
Notes
MRI uses the magnetic nature of hydrogen nuclei to image a patient's tissues. Hydrogen nuclei are abundant, because the body is largely composed of water, H2O.
Keywords
magnetic resonance imaging, MRI, nuclear magnetic resonance, NMR, spectroscopy, nucleus, magnet, energy
09-24
Title
A nucleus can assume a high energy or low energy state in a magnetic field
Caption
The energies (and therefore the orientations) of a nucleus in an external magnetic field are quantized. Electromagnetic radiation of the correct energy causes a transition from one orientation to the other.
Notes
MRI relies on a magnetic field that varies over space.
Keywords
magnetic resonance imaging, MRI, nuclear magnetic resonance, NMR, spectroscopy, nucleus, magnet, energy
09-25-02un
Title
Orbital diagram for a ground state hydrogen atom
Caption
The arrow represents the electron; the electron is in the ground state because it is in the lowest-energy shell and subshell possible.
Notes
The arrow suggests that the electron has a magnetic field; the magnetic field can point either up ("north") or down ("south").
Keywords
energy, electron, quantum-mechanical, quantum number, orbital, shell, subshell, ground state, hydrogen
09-25-03un
Title
Orbital diagram and electron configuration for a ground state helium atom
Caption
The orbital diagram and electron configuration are both ways to show how electrons are organized in an atom. In this case, the helium atom contains a pair of electrons in a 1s orbital. The arrows represent the electrons; the electrons are in the ground state because they are in the lowest-energy shell and subshell possible, and because their magnetic fields are aligned to attract one another.
Notes
The arrow suggests that the electron has a magnetic field; the magnetic field can point either up ("north") or down ("south").
Keywords
energy, electron, quantum-mechanical, quantum number, orbital, shell, subshell, ground state, helium, electron configuration
09-26
Title
Energy ordering of orbitals for multi-electron atoms
Caption
Energy ordering for multi-electron atoms. Different subshells within the same principal shell have different energies.
Notes
The more complex the subshell, the higher its energy. This explains why the 3d subshell is higher in energy than the 4s subshell.
Keywords
energy, electron, quantum-mechanical, quantum number, orbital, shell, subshell, electron configuration
09-26-01un
Title
Orbital diagram and electron configuration for a ground state lithium atom
Caption
The orbital diagram and electron configuration are both ways to show how electrons are organized in an atom. In this case, the lithium atom contains a pair of electrons in a 1s orbital. The third electron fits into the next lowest-energy subshell, the 2s.
Notes
The arrow suggests that the electron has a magnetic field; the magnetic field can point either up ("north") or down ("south").
Keywords
energy, electron, quantum-mechanical, quantum number, orbital, shell, subshell, ground state, lithium, electron configuration
09-26-02un
Title
Orbital diagram and electron configuration for a ground state carbon atom
Caption
The orbital diagram and electron configuration are both ways to show how electrons are organized in an atom. In this case, the carbon atom contains a pair of electrons in a 1s orbital, another pair in 2s, and a final pair in 2p.
Notes
The arrow suggests that the electron has a magnetic field; the magnetic field can point either up ("north") or down ("south"). The electrons fill subshells in order of increasing energy.
Keywords
energy, electron, quantum-mechanical, quantum number, orbital, shell, subshell, ground state, carbon, electron configuration
09-27
Title
A scheme for filling orbitals
Caption
The arrows indicate the order in which orbitals fill.
Notes
This information is encoded into the periodic table.
Keywords
energy, electron, quantum-mechanical, quantum number, orbital, shell, subshell, ground state, electron configuration
09-27-01un
Title
Orbital diagram and electron configuration for eight elements in the ground state
Caption
The orbital diagram and electron configuration are both ways to show how electrons are organized in an atom.
Notes
The arrow suggests that the electron has a magnetic field; the magnetic field can point either up ("north") or down ("south"). The electrons fill subshells in order of increasing energy.
Keywords
energy, electron, quantum-mechanical, quantum number, orbital, shell, subshell, ground state, electron configuration
09-27-03un
Title
Orbital diagram for silicon
Caption
The orbital diagram and electron configuration are both ways to show how electrons are organized in an atom. Note that no orbital ever contains more than two electrons.
Notes
The arrow suggests that the electron has a magnetic field; the magnetic field can point either up ("north") or down ("south"). The electrons fill subshells in order of increasing energy.
Keywords
energy, electron, quantum-mechanical, quantum number, orbital, shell, subshell, ground state, silicon, electron configuration
09-27-04un
Title
Orbital diagram for argon
Caption
The orbital diagram and electron configuration are both ways to show how electrons are organized in an atom. Note that no orbital ever contains more than two electrons. For argon, all sublevels are full, putting the atom at especially low energy.
Notes
The arrow suggests that the electron has a magnetic field; the magnetic field can point either up ("north") or down ("south"). The electrons fill subshells in order of increasing energy.
Keywords
energy, electron, quantum-mechanical, quantum number, orbital, shell, subshell, ground state, argon, electron configuration
09-27-05un
Title
Silicon's valence electrons
Caption
The electrons in silicon's outermost principal shell are at highest energy. The high-energy electrons are chemically the most active; since chemically active electrons are of interest to chemists, chemists have named these electrons the valence electrons. Silicon has four valence electrons.
Notes
Valence electrons are responsible for most of the chemical behavior that we observe.
Keywords
energy, electron, quantum-mechanical, quantum number, orbital, shell, subshell, valence electron, electron configuration, silicon
09-27-06un
Title
Selenium's valence electrons
Caption
The electrons in selenium's outermost principal shell are at high energy. The high-energy electrons are chemically the most active; since chemically active electrons are of interest to chemists, chemists have named these electrons the valence electrons. Selenium has six valence electrons.
Notes
Valence electrons are responsible for most of the chemical behavior that we observe.
Keywords
energy, electron, quantum-mechanical, quantum number, orbital, shell, subshell, valence electron, electron configuration, selenium
09-27-07un
Title
Chlorine's valence electrons
Caption
The electrons in chlorine's outermost principal shell are at high energy. The high-energy electrons are chemically the most active; since chemically active electrons are of interest to chemists, chemists have named these electrons the valence electrons. Chlorine has seven valence electrons.
Notes
Valence electrons are responsible for most of the chemical behavior that we observe.
Keywords
energy, electron, quantum-mechanical, quantum number, orbital, shell, subshell, valence electron, electron configuration, chlorine
09-28
Title
Outer electron configuration for the first 18 elements
Caption
The valence electrons for elements in a group (column) will have a similar electron configuration for the valence electrons. The only difference will be which shell holds the valence electrons.
Notes
The group number equals the number of valence electrons.
Keywords
energy, electron, quantum-mechanical, quantum number, orbital, shell, subshell, valence electron, electron configuration, group, period
09-29
Title
Outer electron configuration for the elements
Caption
The valence electrons for elements in a group (column) will have a similar electron configuration for the valence electrons. The only difference will be which shell holds the valence electrons.
Notes
In general, the group number equals the number of valence electrons.
Keywords
energy, electron, quantum-mechanical, quantum number, orbital, shell, subshell, valence electron, electron configuration, group, period
09-30
Title
The periodic table gives the electron configuration for P
Caption
The electron configuration can be determined by the periodic table because the shell and subshell information is embedded in the table.
Notes
The inner electron configuration is that of the noble gas at the end of the previous row (Ne); the row number gives the shell, and the location of the elements in the row containing P tells where the valence electrons are located: 3s23p3. Overall, the configuration is [Ne]3s23p3.
Keywords
energy, electron, quantum-mechanical, quantum number, orbital, shell, subshell, valence electron, electron configuration, group, period, phosphorus
09-31
Title
The periodic table gives the electron configuration for As
Caption
The electron configuration can be determined by the periodic table because the shell and subshell information is embedded in the table.
Notes
The inner electron configuration is that of the noble gas at the end of the previous row (Ar); the row number gives the shell, and the location of the elements in the row containing As tells where the d-subshell and valence electrons are located: 4s23d104p3. Overall, the configuration is [Ar]4s23d104p3.
Keywords
energy, electron, quantum-mechanical, quantum number, orbital, shell, subshell, valence electron, electron configuration, group, period, arsenic
09-32
Title
The noble gases have filled valence subshells
Caption
The noble gases (except for helium) all have 8 valence electrons and completely full outer principal shells.
Notes
The noble gases are at low energy because their subshells are full. Low energy means low chemical reactivity.
Keywords
energy, electron, quantum-mechanical, quantum number, orbital, shell, subshell, valence electron, electron configuration, group, period, noble gas
09-33
Title
The alkali metals have only one valence electron
Caption
The alkali metals all have ns1 electron configurations and are therefore one electron beyond a noble gas configuration. In their reactions, they tend to lose that electron, forming +1 ions and attaining a noble gas configuration.
Notes
The alkali metals are reactive because they give up their valence electron very readily.
Keywords
energy, electron, quantum-mechanical, quantum number, orbital, shell, subshell, valence electron, electron configuration, group, period, alkali metal
09-34
Title
The alkaline earth metals have two valence electrons
Caption
The alkaline earth metals all have ns2 electron configurations and are therefore two electrons beyond a noble gas configuration. In their reactions, they tend to lose two electrons, forming +2 ions and attaining a noble gas configuration.
Notes
The alkaline earth metals are reactive because they give up their valence electrons readily. Students might be asked to explain why the alkali metals are more reactive than the alkaline earth metals.
Keywords
energy, electron, quantum-mechanical, quantum number, orbital, shell, subshell, valence electron, electron configuration, group, period, alkaline earth
09-35
Title
The halogens have seven valence electrons
Caption
The halogens all have ns2np5 electron configurations and are therefore one electron short of a noble gas configuration. In their reactions, they tend to gain one electron, forming -1 ions and attaining a noble gas configuration.
Notes
The halogens are reactive because they need only one valence electron to get to low energy.
Keywords
energy, electron, quantum-mechanical, quantum number, orbital, shell, subshell, valence electron, electron configuration, group, period, halogen
09-36
Title
Ion charges by group
Caption
Elements within a group will form ions of the same charge because they have the same number of valence electrons.
Notes
Metals will lose their valence electrons when they form ions; nonmetals will gain valence electrons when they form ions. In both cases, the elements seek electron configurations like those in the noble gases.
Keywords
ion, anion, cation, periodic table, group, electron
09-37
Title
Ionization energy trends in the periodic table
Caption
Ionization energy increases as you move to the right across a period and decreases as you move down a column in the periodic table.
Notes
Ionization energy decreases down a group because the electrons in high quantum number orbitals are held less strongly by the nucleus than are electrons in low-n orbitals. From left to right in a period, ionization energy increases the closer the element gets to a noble gas configuration.
Keywords
ionization energy, ion, anion, cation, group, period, electron
09-37-01i
Title
Which has the higher ionization energy, Mg or P?
Caption
P has a higher ionization energy than Mg, according to the left-to-right ionization trend in the periodic table.
Notes
Ionization energy decreases down a group because the electrons in high quantum number orbitals are held less strongly by the nucleus than are electrons in low-n orbitals. From left to right in a period, ionization energy increases the closer the element gets to a noble gas configuration.
Keywords
ionization energy, ion, anion, cation, group, period, electron
09-37-02j
Title
Which has the higher ionization energy, As or Sb?
Caption
As has a higher ionization energy than Sb, according to the top-to-bottom ionization trend in the periodic table.
Notes
Ionization energy decreases down a group because the electrons in high quantum number orbitals are held less strongly by the nucleus than are electrons in low-n orbitals. From left to right in a period, ionization energy increases the closer the element gets to a noble gas configuration.
Keywords
ionization energy, ion, anion, cation, group, period, electron
09-37-03k
Title
Which has the higher ionization energy, N or Si?
Caption
N has a higher ionization energy than Si, according to both the top-to-bottom and the left-to-right ionization trends in the periodic table.
Notes
Ionization energy decreases down a group because the electrons in high quantum number orbitals are held less strongly by the nucleus than are electrons in low-n orbitals. From left to right in a period, ionization energy increases the closer the element gets to a noble gas configuration.
Keywords
ionization energy, ion, anion, cation, group, period, electron
09-37-04l
Title
Which has the higher ionization energy, O or Cl?
Caption
Here we can't tell which has the higher ionization energy: O would be higher according to the top-to-bottom trend, but Cl would be higher according to the left-to-right ionization trend. The effects tend to cancel.
Notes
Ionization energy decreases down a group because the electrons in high quantum number orbitals are held less strongly by the nucleus than are electrons in low-n orbitals. From left to right in a period, ionization energy increases the closer the element gets to a noble gas configuration.
Keywords
ionization energy, ion, anion, cation, group, period, electron
09-38
Title
Relative atomic sizes of the representative elements
Caption
Atomic size decreases as you move to the right across a period and increases as you move down a column in the periodic table.
Notes
Atomic size increases down a column because orbitals of higher quantum number (n) have their maximum probability farther from the nucleus. Atomic size decreases from left to right in the periodic table because the greater number of protons in the nucleus will exert a greater attraction on the electrons, pulling them closer to the nucleus.
Keywords
atomic size, group, period
09-38-01m
Title
Which has the greater atomic size, C or O?
Caption
C has a greater atomic size than O, according to the left-to-right atomic size trend in the periodic table.
Notes
Atomic size increases down a column because orbitals of higher quantum number (n) have their maximum probability farther from the nucleus. Atomic size decreases from left to right in the periodic table because the greater number of protons in the nucleus will exert a greater attraction on the electrons, pulling them closer to the nucleus.
Keywords
atomic size, group, period
09-38-02n
Title
Which has the greater atomic size, Li or K?
Caption
K has a greater atomic size than Li, according to the top-to-bottom atomic size trend in the periodic table.
Notes
Atomic size increases down a column because orbitals of higher quantum number (n) have their maximum probability farther from the nucleus. Atomic size decreases from left to right in the periodic table because the greater number of protons in the nucleus will exert a greater attraction on the electrons, pulling them closer to the nucleus.
Keywords
atomic size, group, period
09-38-03o
Title
Which has the greater atomic size, C or Al?
Caption
Al has a greater atomic size than C, according to both the top-to-bottom trend and the left-to-right atomic size trend in the periodic table.
Notes
Atomic size increases down a column because orbitals of higher quantum number (n) have their maximum probability farther from the nucleus. Atomic size decreases from left to right in the periodic table because the greater number of protons in the nucleus will exert a greater attraction on the electrons, pulling them closer to the nucleus.
Keywords
atomic size, group, period
09-38-04p
Title
Which has the greater atomic size, Se or I?
Caption
Here we can't tell which has the greater atomic size: I would be higher according to the top-to-bottom trend, but Se would be higher according to the left-to-right ionization trend. The effects tend to cancel.
Notes
Atomic size increases down a column because orbitals of higher quantum number (n) have their maximum probability farther from the nucleus. Atomic size decreases from left to right in the periodic table because the greater number of protons in the nucleus will exert a greater attraction on the electrons, pulling them closer to the nucleus.
Keywords
atomic size, group, period
09-39
Title
Metallic character trends in the periodic table
Caption
Metallic character decreases as you move to the right across a period and increases as you move down a column in the periodic table.
Notes
The text links metallic character to the tendency to lose electrons in chemical reactions, and nonmetallic character to the tendency to gain electrons in chemical reactions. The metallic character trends therefore follow the ionization energy trends.
Keywords
metallic character, group, period, periodic table, ionization energy
09-40
Title
The metallic character trends explain the location of metals, metalloids, and nonmetals
Caption
Metals tend to lie to the left and bottom of the periodic table, where we would expect to find lower ionization energies; nonmetals tend to lie up and to the right in the periodic table, where ionization energies are higher, and metalloids are at the frontier between the two types of elements.
Notes
Students should know what the stairstep line toward the right side of the periodic table represents.
Keywords
metal, nonmetal, metalloid, metallic character, group, period, periodic table, ionization energy
09-40-01q
Title
Which is the more metallic element, Sn or Te?
Caption
Sn is a more metallic element than Te, according to the left-to-right metallic character trend in the periodic table.
Notes
The text links metallic character to the tendency to lose electrons in chemical reactions, and nonmetallic character to the tendency to gain electrons in chemical reactions. The metallic character trends therefore follow the ionization energy trends.
Keywords
metal, nonmetal, metalloid, metallic character, group, period, periodic table, ionization energy
09-40-02r
Title
Which is the more metallic element, Si or Sn?
Caption
Sn is a more metallic element than Si, according to the top-to-bottom metallic character trend in the periodic table.
Notes
The text links metallic character to the tendency to lose electrons in chemical reactions, and nonmetallic character to the tendency to gain electrons in chemical reactions. The metallic character trends therefore follow the ionization energy trends.
Keywords
metal, nonmetal, metalloid, metallic character, group, period, periodic table, ionization energy
09-40-03s
Title
Which is the more metallic element, Br or Te?
Caption
Te is a more metallic element than Br, according to both the top-to-bottom trend and the left-to-right metallic character trend in the periodic table.
Notes
The text links metallic character to the tendency to lose electrons in chemical reactions, and nonmetallic character to the tendency to gain electrons in chemical reactions. The metallic character trends therefore follow the ionization energy trends.
Keywords
metal, nonmetal, metalloid, metallic character, group, period, periodic table, ionization energy
09-40-04t
Title
Which is the more metallic element, Se or I?
Caption
Here we can't tell which has the greater atomic size: I would be more metallic according to the top-to-bottom trend, but Se would be more metallic according to the left-to-right metallic character trend. The effects tend to cancel.
Notes
The text links metallic character to the tendency to lose electrons in chemical reactions, and nonmetallic character to the tendency to gain electrons in chemical reactions. The metallic character trends therefore follow the ionization energy trends.
Keywords
metal, nonmetal, metalloid, metallic character, group, period, periodic table, ionization energy
09-40-05un
Title
Orbital diagram (outer electrons) of Ge
Caption
Ge has the Ar core, with four valence electrons in the 4s and 4p subshells.
Notes
Note that the two electrons in the 4p subshell are in different orbitals. This makes sense, because the electrons, having negative charge, will try to get as far apart from one another as possible. They will reside in different orbitals.
Keywords
orbital diagram, valence electrons, outer electrons, germanium, shell, subshell
09-40-06un
Title
Core electrons and valence electrons in germanium
Caption
Ge has the Ar core, with four valence electrons in the 4s and 4p subshells.
Notes
The valence electrons are in the highest-used shell. In that shell, we find s and p subshells.
Keywords
electron configuration, valence electrons, core electrons, germanium, shell, subshell

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