Which atom will have the highest ionization energy?
Sr Ba
Rb Cs
Answer (2)
Ionization energy increases across a period and decreases down a group.
Sr and Ba are in Group 2; Sr is above Ba, so Sr has higher ionization energy.
Rb and Cs are in Group 1; Rb is above Cs, so Rb has higher ionization energy.
Sr is to the right of Rb, so Sr has higher ionization energy.
Therefore, Sr has the highest ionization energy: S r .
Explanation
Understanding Ionization Energy Trends The problem asks us to identify the atom with the highest ionization energy from the given list: Sr, Ba, Rb, and Cs. Ionization energy is the energy required to remove an electron from an atom. Generally, ionization energy increases across a period (from left to right) and decreases down a group (from top to bottom) in the periodic table.
Locating Atoms on the Periodic Table First, let's locate the positions of the given atoms in the periodic table. Sr (Strontium) and Ba (Barium) are in Group 2 (alkaline earth metals). Rb (Rubidium) and Cs (Cesium) are in Group 1 (alkali metals).
Comparing Within Groups Now, let's compare the ionization energies based on their positions. Within Group 2, Sr is above Ba. Therefore, Sr has a higher ionization energy than Ba. Within Group 1, Rb is above Cs. Therefore, Rb has a higher ionization energy than Cs.
Comparing Across Periods Next, we need to compare Sr and Rb. Sr is to the right of Rb in the periodic table. Elements to the right have higher ionization energies due to increased nuclear charge and decreased atomic radius. Therefore, Sr has a higher ionization energy than Rb.
Conclusion Since Sr has a higher ionization energy than Ba and Rb, and Rb has a higher ionization energy than Cs, we can conclude that Sr has the highest ionization energy among the given atoms.
Examples
Understanding ionization energy is crucial in various fields. For example, in chemistry, it helps predict the reactivity of elements. Elements with low ionization energies, like alkali metals, tend to lose electrons easily and form positive ions, making them highly reactive. In materials science, ionization energy influences the formation of chemical bonds and the electronic properties of materials. For instance, materials with high ionization energies are often used as insulators because they hold onto their electrons tightly. In environmental science, ionization processes play a role in atmospheric chemistry, such as the formation of ions in the ionosphere due to solar radiation. These ions can affect radio wave propagation and communication systems.
Strontium (Sr) has the highest ionization energy compared to Barium (Ba), Rubidium (Rb), and Cesium (Cs). This is because ionization energy increases as you move up a group and across a period in the periodic table. Therefore, the answer is: Sr.
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