The human eye contains a molecule called 11- cis -retinal that changes shape when struck with light of sufficient energy. The change in shape triggers a series of events that results in an electrical signal being sent to the brain. The minimum energy required to change the conformation of 11- cis -retinal within the eye is about 164 kJ/mol. Calculate the longest wavelength visible to the human eye.
Step 1 Elemental Astatine exists only in very tiny quantities and generally for a very short period of time due to its short half-life. Hence the bulk properties of Astatine are not known with certainity.The properties are estimated based on its periodic table position as a heavier analog of iodine and as a member of the halogen family. The general trend in state for halogens is as given below Halogen Family F(gas) Cl(gas) Br(liquid ) I(solid) At(solid) Hence there is a trend in state from gas to liquid to solid down the group. So Astatine is expected to be a solid