To determine which element has the highest electron affinity, we need to understand what electron affinity is. Electron affinity is a measure of the energy change when an electron is added to a neutral atom in the gaseous phase, forming a negative ion. Elements with high electron affinities are more likely to accept an electron.
Here's a step-by-step analysis of the elements provided:
a. Silicon (Si):
Silicon is a metalloid in Group 14 of the periodic table. While it does have some tendency to accept electrons due to its role in semiconductor technology, its electron affinity is not the highest among the given options.
b. Magnesium (Mg):
Magnesium is an alkaline earth metal in Group 2. Generally, Group 2 elements have low electron affinities because they prefer to lose electrons rather than gain them, aiming to achieve the stable configuration of a nearby noble gas.
c. Chlorine (Cl):
Chlorine is a halogen in Group 17. Halogens are known for having high electron affinities because they have seven electrons in their outermost shell and need just one more to achieve a noble gas configuration. This makes them highly receptive to gaining an electron.
d. Phosphorus (P):
Phosphorus is in Group 15. Elements in this group also have relatively high electron affinities, as they need three electrons to achieve a noble gas configuration. However, their affinity is not as high as that of the Group 17 halogens.
Considering this information, Chlorine (Cl), being a halogen, is expected to have the highest electron affinity among the given choices.
Thus, the element that should have the highest electron affinity is:
c. Cl
