Which of the following statements about electronegativity is false? (a) Electronegativity is the ability of an atom in a molecule to attract electron density toward itself. (b) Electronegativity is the same thing as electron affinity. (c) The numerical values for electronegativity have no units. (d) Fluorine is the most electronegative element. (e) Cesium is the least electronegative element.

Verified step by step guidance

1. Step 1: Understand the concept of electronegativity. Electronegativity is a measure of the ability of an atom in a molecule to attract electrons to itself. It is a key concept in understanding the nature of chemical bonds.
2. Step 2: Compare the given statements with the definition and properties of electronegativity. Statement (a) is true as it correctly defines electronegativity.
3. Step 3: Understand the difference between electronegativity and electron affinity. Electron affinity is the energy change that occurs when an electron is added to a neutral atom, while electronegativity is the ability of an atom to attract electrons. Therefore, statement (b) is false.
4. Step 4: Electronegativity is a dimensionless quantity, meaning it has no units. So, statement (c) is true.
5. Step 5: Fluorine is the most electronegative element and cesium is the least electronegative element on the periodic table. Therefore, statements (d) and (e) are also true.

Key Concepts

Electronegativity

Electronegativity is a measure of an atom's ability to attract and hold onto electron density in a chemical bond. It is a relative scale, with values assigned to elements based on their tendency to attract electrons. The most electronegative element is fluorine, which has the highest value on the Pauling scale, indicating its strong ability to pull electron density towards itself.

Electron Affinity

Electron affinity refers to the energy change that occurs when an electron is added to a neutral atom in the gas phase, resulting in the formation of a negative ion. While both electronegativity and electron affinity involve the attraction of electrons, they are distinct concepts; electronegativity pertains to an atom's behavior in a bond, while electron affinity measures the energy change associated with gaining an electron.

Units of Measurement

Electronegativity values are dimensionless and do not have units, as they are based on a relative scale rather than an absolute measurement. This means that electronegativity is expressed as a number that indicates the strength of an atom's attraction for electrons compared to other elements, allowing for easy comparison without the need for specific units.