Electron Affinity Concepts and Trends

This tutorial covers the concept of electron affinity, which is the energy change when an atom gains an electron. It explains that electron affinities are usually negative, indicating energy release, but there are exceptions. The tutorial discusses trends in electron affinity across the periodic table, noting that values become more negative from left to right. Exceptions include noble gases, group 2a, and group 5a elements. Example problems illustrate these concepts, and the tutorial concludes with an explanation of why phosphorus does not follow the general trend.

What is electron affinity?

• The energy required to add a proton to an atom

• The energy required to remove an electron from an atom

• The energy change when an atom gains an electron

• The energy change when an atom loses an electron

Which direction on the periodic table generally shows an increase in negative electron affinity values?

• From left to right

• From bottom to top

• From right to left

• From top to bottom

What happens to electron affinity values as you move from left to right across the periodic table?

• They become more positive

• They become more negative

• They fluctuate randomly

• They remain the same

Why do noble gases have positive electron affinity values?

• They have partially filled shells

• They have a high atomic number

• They have no electrons

• They have completely filled shells

What is the reason for the positive electron affinity values in group 2A elements?

• Electrons are added to a filled s subshell

• Electrons are added to an unoccupied p subshell

• Electrons are added to a filled p subshell

• Electrons are added to a higher energy shell

In group 5A, why is adding an electron less favorable?

• It requires adding to a new shell

• It requires pairing with an existing electron

• It requires adding to a filled d subshell

• It requires adding to a filled s subshell

Which group on the periodic table has elements with more positive electron affinity values than group 4A?

• Group 5A

• Group 1A

• Group 6A

• Group 2A

Which element would have the most negative electron affinity: germanium, potassium, chlorine, or sulfur?

• Germanium

• Potassium

• Chlorine

• Sulfur

Why does phosphorus not follow the general trend for electron affinity?

• It has a half-filled s subshell

• It has a completely filled s subshell

• It has a completely filled p subshell

• It has a half-filled p subshell

What must be overcome when adding an electron to phosphorus?

• Proton-proton repulsions

• Nucleus-electron repulsions

• Electron-electron repulsions

• Neutron-neutron repulsions