Structure 1.3.7—Successive ionization energy (IE) data for an element give information about its electron configuration. AHL
What You’ll Learn:
AHL Only
- Deduce the group of an element from its successive ionization data.
- Databases are useful for compiling graphs of trends in IEs
Keywords
Emission spectra, excited states, lower energy levels, electromagnetic spectrum, wavelength, frequency, energy, continuous spectrum, line spectrum, hydrogen emission spectrum, energy transitions, Balmer series, Lyman series, Paschen series, Rydberg formula, principal quantum number (n), maximum number of electrons, Aufbau principle, main energy level, sublevels (s, p, d, and f), atomic orbitals, s orbital, p orbitals (px, py, and pz),
d orbitals (dxy, dxz, dyz, dx²-y², and dz²), orbital shapes and orientations, nodal planes, electron configuration, chemical environment, opposite spin, Aufbau principle, Hund’s rule, Pauli exclusion principle, full electron configurations, condensed electron configurations, noble gas core, orbital diagrams (arrow-in-box diagrams)
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Syllabus Links
HL Structure 3.1—How do patterns of successive IEs of transition elements help to explain the variable oxidation states of these elements?
Successive ionization energy (IE) data for an element give information about its electron configuration:
Successive ionization energies refer to the energy required to remove electrons from an atom, one at a time. The first ionization energy (IE1) is the energy needed to remove the first electron, the second ionization energy (IE2) is the energy needed to remove the second electron, and so on. As electrons are removed, the ionization energy generally increases because the remaining electrons experience a greater effective nuclear charge, making them more difficult to remove.
Deducing the group of an element from its successive ionization data:
Significant increases in successive ionization energies indicate that an electron is being removed from a more stable, inner energy level (or shell). This can help determine the group number of the element in question. The number of electrons in the valence shell corresponds to the group number of the element.
For example, if there is a large increase in ionization energy between IE2 and IE3, it suggests that the element has two valence electrons, placing it in Group 2 (alkaline earth metals). Similarly, if a significant increase is observed between IE5 and IE6, it indicates that the element has five valence electrons, placing it in Group 15 (pnictogens).
Questions
- The first ionization energies (in kJ/mol) for elements in Period 2 are given: Lithium (Li): 520 Beryllium (Be): 899 Boron (B): 801 Carbon (C): 1086 Nitrogen (N): 1402 Oxygen (O): 1314 Fluorine (F): 1681 Neon (Ne): 2081Plot a graph of the first ionization energies for these elements in Period 2. Describe the trend observed and discuss the reasons behind any discontinuities.
- Consider the successive ionization energies (in kJ/mol) of an unknown element X: IE1: 577 IE2: 1817 IE3: 3931 IE4: 6276 IE5: 15076 IE6: 17902 IE7: 21078Plot a graph of the successive ionization energies for element X. Identify the group in the periodic table that element X belongs to based on the trend observed in the graph. Extension plot the same graph, but plot the Natural Log of the ionisation energies, why do you think this is the most common way this data is represented?
- The first ionization energies (in kJ/mol) for elements in Group 1 (alkali metals) are given: Lithium (Li): 520 Sodium (Na): 496 Potassium (K): 419 Rubidium (Rb): 403 Cesium (Cs): 376 Francium (Fr): 370Plot a graph of the first ionization energies for these elements in Group 1. Describe the trend observed and explain the reason behind the trend.
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