Which of the following elements has the lowest electronegativity?

• A. Cl
• B. O
• C. Cs
• D. Na

Answer: (C)

Verified step by step guidance

1. Understand that electronegativity is a measure of an atom's ability to attract and hold onto electrons in a chemical bond.
2. Recall the general trend of electronegativity on the periodic table: it increases from left to right across a period and decreases from top to bottom down a group.
3. Identify the positions of the given elements on the periodic table: Cl (chlorine) and O (oxygen) are nonmetals located towards the right and top of the table, while Na (sodium) and Cs (cesium) are metals located on the left side, with Cs being further down the group than Na.
4. Since electronegativity decreases down a group, Cs, being the lowest and furthest left among the options, will have the lowest electronegativity.
5. Therefore, by comparing their positions and applying the periodic trends, conclude that Cs has the lowest electronegativity among the given elements.