Final answer:
Electronegativity is the ability of an element to attract electrons in a chemical bond, with fluorine having the highest and francium the lowest values on the Pauling scale.
Step-by-step explanation:
The electronegativity of an element is its ability to attract electrons within a chemical bond. On the Pauling scale, electronegativity values range from about 0.7 for francium (Fr) to 4.0 for fluorine (F), which has the highest electronegativity. The electronegativity generally increases across the periodic table from left to right and decreases down a group. This property affects the bond polarity and ionic character of compounds formed by elements, with higher electronegativity differences leading to more polar bonds.
For example, in covalent bonds between atoms with different electronegativities, the electron density will be greater around the more electronegative atom. Additionally, elements that can expand their valence shell beyond eight electrons may form compounds with unusual electron distributions, affecting their chemical reactivity and bond formation. Conversely, elements with low electronegativities tend to be metals and behave as reductants in reactions.