Strontium, a group 2 element with an electron configuration of 1s22s22p63s23p64s23d04p65s, will form a
in a chemical bond.
ion
-1
+1
-2
+2

Evaporation: this is when warmth from the sun causes water from oceans, lakes, streams, ice and soils to rise into the air and turn into water vapour (gas). water vapour droplets join together to make clouds! condensation: this is when water vapour in the air cools down and turns back into liquid water.

Because a model would make the investigation easier to understand

13) a 14) a15) b16) i don't know sorry17) a (maybe)