The elements beryllium, calcium, and strontium are all in group 2. What is the correct relationship of these elements regarding their ionization energy?
A. $Ca < Be < Sr$
B. $Sr < Be < Ca$
C. $Be < Ca < Sr$
D. $Sr < Ca < Be$
E. $Ca < Sr < Be$
Answer (1)
Ionization energy decreases down a group.
Elements are ordered Be, Ca, Sr.
Therefore, Sr < Ca < Be.
The correct relationship is S r < C a < B e
Explanation
Understanding the Problem The elements beryllium (Be), calcium (Ca), and strontium (Sr) are all in group 2 of the periodic table. We need to determine the correct relationship between these elements regarding their ionization energy. Ionization energy is the energy required to remove an electron from an atom or ion in the gaseous phase.
Ionization Energy Trend Ionization energy generally decreases as you move down a group in the periodic table. This is because the outermost electrons are farther from the nucleus and are shielded by more inner electrons, making them easier to remove.
Element Order and Ionization Energy The order of the elements in Group 2 is beryllium (Be), calcium (Ca), and strontium (Sr), from top to bottom. Therefore, the ionization energy should decrease in the order Be > Ca > Sr.
Determining the Relationship This means that strontium (Sr) has the lowest ionization energy, followed by calcium (Ca), and beryllium (Be) has the highest ionization energy. So, the correct relationship is Sr < Ca < Be.
Final Answer The correct answer is D. S r < C a < B e
Examples
Understanding ionization energy is crucial in various real-world applications. For instance, in designing solar cells, materials with lower ionization energies are preferred as they readily release electrons when exposed to light, enhancing the cell's efficiency. Similarly, in chemical reactions, elements with lower ionization energies tend to be more reactive, influencing the synthesis of new compounds. This concept also plays a vital role in understanding the behavior of elements in batteries and other energy storage devices.
