Which of the following elements has the largest ionization energy?

• A. Ne (Neon)
• B. Na (Sodium)
• C. K (Potassium)
• D. Li (Lithium)

Answer: (A)

Verified step by step guidance

1. Understand that ionization energy is the energy required to remove an electron from a gaseous atom or ion. It generally increases across a period (left to right) on the periodic table and decreases down a group (top to bottom).
2. Identify the positions of the given elements on the periodic table: Li, Na, and K are all alkali metals in Group 1, with Li at the top, Na below it, and K further down. Ne is a noble gas in Group 18, located at the far right of the same period as Na.
3. Recall that noble gases have very high ionization energies because they have full valence electron shells, making them very stable and less willing to lose electrons.
4. Compare the ionization energies by considering both group and period trends: ionization energy increases across a period from left to right and decreases down a group from top to bottom. Since Ne is to the right of Li, Na, and K and is a noble gas, it will have the highest ionization energy.
5. Conclude that among the given elements, Ne (Neon) has the largest ionization energy due to its position as a noble gas with a full valence shell and its location at the far right of the periodic table.