Periodic Trends- Electron Affinity
Electronegativity- a measure of the tendency of an atom to attract
electrons while in a compound or molecule.
A numerical value given to an atom from 0-4.0 “Pauling Scale” Fluorine is the MOST electronegative element; 4.0
PERIOD TREND: electronegativity increases from left to right Non-metals naturally WANT to gain valence electrons- so stronger pull on the electrons in a compound. GROUP TREND: electronegativity decreases from top to bottom( or sort of stay the same)
The bonding electrons are further away from the nucleus of the other atom so the attraction to the nucleus is less • In General ~ Metals have low electronegativites; Non-metals have high electronegativities • Can help to tell us if electrons are shared equally or unequally in a molecule or compound. http://study.com/academy/lesson/electronegativity-trends-among-groups-andperiods-of-the-periodic-table.html
Electron affinity- the energy change that occurs when an electron is ADDED to an atom. • AKA: when an ANION IS MADE PERIOD TREND: increases left to right(nonmetals have a higher affinity for electrons) GROUP TREND: decreases down a group…. For the most part…this is due to the size of the radius.
If a negative value • Energy is released when electrons are gained ( the more neg. the value- the easier the atom acquires electrons) • A + e’ --- A- + energy released ( non-metals) • If a positive value (0) • Energy is ABSORBED when electrons are gained- these atoms have a more difficult time acquiring electrons.
A + e’ + energy absorbed----- A- ( metals)
http://chemteacher.che meddl.org/services/che mteacher/index.php?opt ion=com_content&view= article&id=90
electrons while in a compound or molecule.
A numerical value given to an atom from 0-4.0 “Pauling Scale” Fluorine is the MOST electronegative element; 4.0
PERIOD TREND: electronegativity increases from left to right Non-metals naturally WANT to gain valence electrons- so stronger pull on the electrons in a compound. GROUP TREND: electronegativity decreases from top to bottom( or sort of stay the same)
The bonding electrons are further away from the nucleus of the other atom so the attraction to the nucleus is less • In General ~ Metals have low electronegativites; Non-metals have high electronegativities • Can help to tell us if electrons are shared equally or unequally in a molecule or compound. http://study.com/academy/lesson/electronegativity-trends-among-groups-andperiods-of-the-periodic-table.html
Electron affinity- the energy change that occurs when an electron is ADDED to an atom. • AKA: when an ANION IS MADE PERIOD TREND: increases left to right(nonmetals have a higher affinity for electrons) GROUP TREND: decreases down a group…. For the most part…this is due to the size of the radius.
If a negative value • Energy is released when electrons are gained ( the more neg. the value- the easier the atom acquires electrons) • A + e’ --- A- + energy released ( non-metals) • If a positive value (0) • Energy is ABSORBED when electrons are gained- these atoms have a more difficult time acquiring electrons.
A + e’ + energy absorbed----- A- ( metals)
http://chemteacher.che meddl.org/services/che mteacher/index.php?opt ion=com_content&view= article&id=90
