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Ch.8 - Periodic Properties of the Elements
Chapter 8, Problem 78

Consider this set of ionization energies. IE1 = 578 kJ/mol IE2 = 1820 kJ/mol IE3 = 2750 kJ/mol IE4 = 11,600 kJ/mol To which third-period element do these ionization values belong?

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Ionization Energy

Ionization energy is the amount of energy required to remove an electron from an atom or ion in its gaseous state. It is a key indicator of an element's reactivity and can vary significantly among different elements. Generally, ionization energy increases across a period in the periodic table due to increasing nuclear charge, which holds electrons more tightly.
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Trends in Ionization Energies

Ionization energies exhibit specific trends in the periodic table. As you move from left to right across a period, ionization energy tends to increase due to the greater effective nuclear charge experienced by the outer electrons. Conversely, as you move down a group, ionization energy decreases because the outer electrons are further from the nucleus and experience more shielding from inner electrons.
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Identification of Elements

To identify an element based on its ionization energies, one can compare the given values to known ionization energies of elements in the same period. The significant jump in ionization energy values, particularly between IE3 and IE4, suggests that the element has a stable electron configuration after losing three electrons, indicating it is likely a non-metal in the third period, such as phosphorus or sulfur.
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