Which group in the periodic table is characterized by high ionization energies but very weak electron affinities?

• A. Alkali metals (Group 1)
• B. Alkaline earth metals (Group 2)
• C. Noble gases (Group 18)
• D. Halogens (Group 17)

Answer: (C)

Verified step by step guidance

1. Understand the concepts of ionization energy and electron affinity: Ionization energy is the energy required to remove an electron from an atom, while electron affinity is the energy change when an atom gains an electron.
2. Recall that elements with high ionization energies hold their electrons tightly, making it difficult to remove electrons.
3. Recognize that weak electron affinity means the atom does not easily gain electrons or releases very little energy when it does.
4. Consider the properties of each group: Alkali metals (Group 1) have low ionization energies and tend to lose electrons easily; Alkaline earth metals (Group 2) have moderate ionization energies; Halogens (Group 17) have high electron affinities because they readily gain electrons.
5. Identify that Noble gases (Group 18) have very high ionization energies because their electron shells are full, and they have very weak electron affinities since they are stable and do not tend to gain electrons.