Chemistry Regents Practice Test

Which of the following elements is likely to have the highest electronegativity?

1. Francium

2. Sodium

3. Chlorine

4. Calcium

The correct answer is: Chlorine

Chlorine is likely to have the highest electronegativity among the listed elements. Electronegativity is a measure of an atom's ability to attract and hold onto electrons when it forms a chemical bond. In general, electronegativity increases from left to right across a period on the periodic table and decreases from top to bottom within a group. Chlorine is located in Group 17 (the halogens) and in Period 3 of the periodic table. Being a nonmetal, it has a high tendency to attract electrons to achieve a stable electron configuration, specifically the octet, which makes it very electronegative. In contrast, francium is located in Group 1 and is one of the least electronegative elements due to its position at the bottom of the alkali metals, where the ability to attract electrons significantly decreases. Sodium, also an alkali metal in Group 1, exhibits low electronegativity for similar reasons, being further left in the periodic table. Calcium, a Group 2 alkaline earth metal, has even less electronegativity than sodium. Consequently, chlorine, with its high electronegativity resulting from its position in the periodic table and its nonmetal character, stands