Question

Which of the following has the highest ionization energy?

• A. Lithium
• B. Beryllium
• C. Fluorine
• D. Neon

Hint:

Ionization energy increases across a period and decreases down a group. Noble gases have the highest values.

Answer 1

The Correct Option is D

To determine which element has the highest ionization energy, we need to consider periodic trends. Ionization energy is the energy required to remove an electron from a gaseous atom. In the periodic table, ionization energy increases across a period from left to right and decreases down a group. This trend is due to the increasing effective nuclear charge across a period, which causes electrons to be more strongly attracted to the nucleus.

Analyzing the given options:

• Lithium (Li) is in Group 1, Period 2
• Beryllium (Be) is in Group 2, Period 2
• Fluorine (F) is in Group 17, Period 2
• Neon (Ne) is in Group 18, Period 2

All these elements belong to the same period (Period 2), so we compare them based on their group. As we move from left to right across a period, ionization energy increases due to the effective nuclear charge. Thus, among these elements, Neon (Ne), being the rightmost and a noble gas, will have the highest ionization energy. Noble gases have fully filled outer electron shells which makes them very stable and require more energy to remove an electron.

Therefore, Neon has the highest ionization energy among the given options.