A. CI, Br
Explanation:
Different kinds of atoms bind their valence electrons with various amounts of energy. In order to remove the valence electrons, enough energy must be available.
The amount of energy required for the removal of an electron is the ionization energy or ionization potential.
The ionization energy depends on:
- Nuclear charge
- Atomic radius
- Sublevel accomodating the electron to be removed.
- Special stability of half or fully filled sublevels.
Across a period, the ionization energy increases.
Down a group ionization energy decreases due to increasing atomic radii.
Cl and Br are in the same periodic group. Cl is element number 2 and Br is element 3 in the group of the halogens.
Therefore, Cl will have a higher ionization energy compared to Br.
Learn more:
Ionization energy brainly.com/question/2153804
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