Using the heating curve of tin, calculate the amount of heat necessary to vaporize 54.0-g of liquid tin with an initial temperature of 100.0°C and it is heated to 365°C until it changes into a gas. The initial and final
temperatures are marked on the graph in green. Give the individual amount of energy for each section and
total energy used.

Br > Se > Ge > K> Ca

Explanation:

Generally in the periodic table, we know that electron affinity increases across a period. Electron affinity refers to the energy released when an extra electron is added to a neutral gaseous atom. Most times, the addition of an electron leads to the formation of a uninegative ion.

The sequence of decrease in electro affinity values appears to be consistent until we get to calcium and potassium. One would have ordinarily expected potassium to have a lower electron affinity than calcium. However, if potassium accepts an electron, that electron goes on to fill the 4s level. This process is more exothermic than in the case of calcium where the extra electron is added to the 3d level. The energy difference between the 4s and 3d levels is enough to make the process less exothermic (only 2.37KJmol-1) compared to that of potassium (48.4 KJmol-1). This explains the order of arrangement seen in the answer above.