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What is the ionization energy of an atom?
What is the ionization energy of an atom?
The minimum amount of energy required to remove the outermost electron from an isolated gaseous atom in its ground state.
What is the unit of ionization enthalpy?
What is the unit of ionization enthalpy?
kJ mol-1
Is the process of ionization generally endothermic or exothermic?
Is the process of ionization generally endothermic or exothermic?
Endothermic
What is the difference between the first and second ionization enthalpy?
What is the difference between the first and second ionization enthalpy?
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How is the theoretical ionization energy calculated?
How is the theoretical ionization energy calculated?
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How are ionization energies measured experimentally?
How are ionization energies measured experimentally?
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What is the trend of the first ionization energy in the periodic table?
What is the trend of the first ionization energy in the periodic table?
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What explains the substantial increase in ionization energy from hydrogen to helium?
What explains the substantial increase in ionization energy from hydrogen to helium?
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What is the effect of increasing atomic size on ionization enthalpy?
What is the effect of increasing atomic size on ionization enthalpy?
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What is the electron configuration of Nitrogen (N)?
What is the electron configuration of Nitrogen (N)?
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How does an increase in nuclear charge affect ionization enthalpy?
How does an increase in nuclear charge affect ionization enthalpy?
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Why does an electron in a doubly occupied p orbital require less energy to remove?
Why does an electron in a doubly occupied p orbital require less energy to remove?
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What is the effect of shielding on the nuclear charge experienced by the outermost electron?
What is the effect of shielding on the nuclear charge experienced by the outermost electron?
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What is the reason for the decrease in ionization energy from P to S?
What is the reason for the decrease in ionization energy from P to S?
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What is the order of screening effect among s, p, d, and f orbitals?
What is the order of screening effect among s, p, d, and f orbitals?
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Why is the ionization energy for Zn higher than for Ga?
Why is the ionization energy for Zn higher than for Ga?
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Why does the ionization energy of s electrons decrease in the order s > p > d > f?
Why does the ionization energy of s electrons decrease in the order s > p > d > f?
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What is the general trend for ionization energy in the periodic table?
What is the general trend for ionization energy in the periodic table?
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Where are metals located in the periodic table?
Where are metals located in the periodic table?
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Why does Be have a lower ionization energy than B?
Why does Be have a lower ionization energy than B?
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What are the elements that border the staircase called?
What are the elements that border the staircase called?
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Why does Mg have a higher ionization energy than Al?
Why does Mg have a higher ionization energy than Al?
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Why are half-filled and completely filled subshells more stable than otherwise filled subshells?
Why are half-filled and completely filled subshells more stable than otherwise filled subshells?
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Why are metals easily oxidized?
Why are metals easily oxidized?
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What is the energy change known as when an electron is added to a neutral gaseous atom in its ground state?
What is the energy change known as when an electron is added to a neutral gaseous atom in its ground state?
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Why are electron affinities usually reported as positive numbers despite being a negative process?
Why are electron affinities usually reported as positive numbers despite being a negative process?
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What is the trend of electron affinities in the periodic table?
What is the trend of electron affinities in the periodic table?
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How does the size of an atom affect its electron gain enthalpy?
How does the size of an atom affect its electron gain enthalpy?
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What is the effect of effective nuclear charge on electron gain enthalpy?
What is the effect of effective nuclear charge on electron gain enthalpy?
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Why do elements of group 18 have positive electron gain enthalpies?
Why do elements of group 18 have positive electron gain enthalpies?
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What happens to the electron added to an atom as you progress down a column?
What happens to the electron added to an atom as you progress down a column?
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What can explain the exceptions to the general periodic trend of electron affinities?
What can explain the exceptions to the general periodic trend of electron affinities?
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Study Notes
Ionization Energy
- Ionization energy is the minimum energy required to remove an outermost electron from an isolated gaseous atom in its ground state.
- The unit of ionization energy is kJ/mol-1, formerly ev and kcal/mol-1.
- It is generally an endothermic process (∆H = +).
- Theoretical ionization energies can be calculated using the equation: I.E = (R∞ * Z*^2) / (n^2 * NΑ), where R∞ is the Rydberg constant, Z* is the effective nuclear charge, n is the principal quantum number, and NΑ is Avogadro's number.
- Experimentally, ionization energies are measured using photoelectron spectroscopy (PES).
Factors Affecting Ionization Energy
- Atomic size: As atomic size increases, the attraction of the nucleus on the outermost electron decreases, and ionization energy decreases.
- Nuclear charge: As nuclear charge increases, ionization energy increases.
- Shielding of outer electrons: Inner electrons neutralize part of the nuclear charge experienced by the outermost electron, leading to a decrease in ionization energy.
- Nature of the orbital: Ionization energy decreases in the order s > p > d > f, as the electron cloud density near the nucleus affects the energy required to remove an electron.
Ionization Energy Exceptions
- Be and B have lower ionization energies due to the electron configuration, where electrons in p orbitals are higher in energy and further from the nucleus than electrons in s orbitals.
- N and O have lower ionization energies due to the removal of an electron from a doubly occupied p orbital, which is repelled by the other electron and requires less energy to remove.
- Zn has a higher ionization energy than Ga due to the removal of an electron from a stable filled 3d subshell in Zn, whereas the removal of an electron from Ga leads to a stable electron configuration.
Electron Affinity (Electron Gain Enthalpy)
- Electron gain enthalpy is the enthalpy change when an electron is added to a neutral gaseous atom in its ground state.
- The energy of this process is known as the electron gain enthalpy, which is usually negative but can be positive for noble gases.
- Electron affinity (E.A.) has the same magnitude but the opposite sign of the electron gain enthalpy.
Factors Affecting Electron Affinity
- Atomic size: As size increases, the magnitude of ∆egH decreases, e.g., down the group 1 and group 17.
- Effective nuclear charge (ENC): As ENC increases, ∆egH increases, e.g., along the second period.
- Progressing down a column, the electron is added to a quantum level farther from the nucleus, resulting in a lower E.A.
Electron Affinity Exceptions
- There are exceptions to the general periodic trend, e.g., N, C, and Ne have lower E.A. than expected due to their electron configurations.
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Description
This quiz covers the concept of ionization energy, also known as ionization potential or ionization enthalpy, which is the minimum energy required to remove an outermost electron from a gaseous atom. It involves the enthalpy change and units of measurement.
