Adecrease in temperature will affect vapor pressure by:

a. increasing the density of the gas molecules, thus making them heavier and more difficult to move around

b. decreasing the surface area of the gas molecules, thus decreasing the number of collisions occurring

c. increasing the rate of condensation

d. decreasing the average kinetic energy of the molecules, making them move slower and collide less

The correct option is D

Explanation:

Vapour pressure is the pressure exerted by vapour on it's solid or liquid form. When temperature increases, vapour pressure increases as the increase in the temperature causes the average kinetic energy of the vapour molecules to increase; this forces the molecules to collide more with each other and it's solid or liquid form.

When the temperature is reduced, the vapour molecules are relaxed and hence the average kinetic energy of the vapour molecules is reduced. When this happens, the vapour molecules move slower and collide less.

explanation:

metals have excess of electrons whereas non-metals have deficiency of electrons. thus, in order to gain stability metals easily donate their electrons to the non-metals.

for example, electronic configuration of sodium is and electronic configuration of phosphorous is .

when a phosphorous atom and sodium atom combine together then sodium will donate is extra one electron to the phosphorous atom. as a result there will be formation of ionic bond between sodium and phosphorous.

the reaction will be as follows.

there, are three sodium sodium atoms and each of them will donate its one extra electron to phosphorous atom. thus, the sub-shell of phosphorous gets completely filled.  

thus, we can conclude that electrons are transferred from atoms of sodium to atoms of phosphorous. this transfer makes the sodium atoms donate one electron and the phosphorous atoms to gain one electron. as a result, the sodium and phosphorus atoms strongly attract each other.

there are two significant figures.