I am reviewing my test and I having trouble figuring out the answer to the following question:
List the following element symbols in order of decreasing exothermic electron affinity: Al, Ca, As
_______>________>________
I wrote: Al>As>Ca (I got it wrong)
I know that if it is favorable to pick up an electron, energy will be released yet, I am still confused about what is the correct answer. Thank you!
As is the right most element in the periodic table (of the three elements); I would pick that as the highest.
Ca is the left most element in the table; I would pick that as the lowest. Al must be between. You can look up the electron affinities at www.webelements.com
Thank you, I guess I got confused with Al and As :)
To determine the correct order of decreasing exothermic electron affinity for the given elements (Al, Ca, As), we need to understand the concept of electron affinity and how it relates to the periodic table.
Electron affinity refers to the amount of energy released when an atom gains an electron to form a negative ion. In general, atoms with high electron affinity have a strong tendency to gain electrons and release energy in the process.
To find the correct order, we can compare the positions of the elements in the periodic table. Generally, as we move from left to right across a period, the electron affinity tends to increase. Similarly, as we move down a group, the electron affinity generally decreases.
Aluminum (Al) is located in Group 13 and period 3. It is to the left of Calcium (Ca) and has a higher atomic number. As we move from left to right across period 3, the electron affinity generally increases. Therefore, Aluminum likely has a higher electron affinity than Calcium.
Arsenic (As) is located in Group 15 and period 4. It is to the right of Aluminum and Calcium and has a higher atomic number compared to both elements. Moving from left to right across period 4, the electron affinity generally increases as well. Hence, Arsenic is likely to have a higher electron affinity than both Aluminum and Calcium.
Based on these observations, the correct order of decreasing exothermic electron affinity would be:
As > Al > Ca
Therefore, the correct answer is As > Al > Ca.