Periodic Trends: Electronegativity and Electron Affinity
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What is electronegativity?
Electronegativity is the tendency of an atom to attract electrons towards itself in a chemical bond.
How does electronegativity change across a period?
Electronegativity increases across a period from left to right.
Why does electronegativity increase across a period?
Electronegativity increases due to greater nuclear charge, attracting bonding electrons more strongly.
How does electronegativity change down a group?
Electronegativity decreases down a group.
Why does electronegativity decrease down a group?
The decrease is due to increased distance and shielding, reducing the nucleus' pull on bonding electrons.
Which element is the most electronegative?
Fluorine is the most electronegative element.
What is electron affinity?
Electron affinity is the energy change that occurs when an electron is added to an isolated atom.
How does electron affinity change across a period?
Electron affinity generally becomes more negative across a period.
Why does electron affinity become more negative across a period?
As nuclear charge increases, atoms more readily accept an additional electron, releasing energy.
How does electron affinity change down a group?
Electron affinity becomes less negative down a group.
Explain the exception in the trend of electron affinity.
Some elements like noble gases and certain second-period elements show less predictable electron affinity due to full or half-full subshells.
Which group in the periodic table generally has the highest electron affinity?
The halogens (Group 17) generally have the highest electron affinity.
What is the relationship between electronegativity and electron affinity?
Both electronegativity and electron affinity indicate an atom's tendency to attract electrons, but electronegativity applies to bonded atoms while electron affinity applies to isolated atoms.
Why do noble gases have low electronegativity and electron affinity?
Noble gases have complete valence shells, making them stable and not inclined to attract additional electrons.
How does atomic size affect electronegativity?
Larger atomic size generally leads to lower electronegativity as the valence electrons are farther from the nucleus' pull.