The valence electrons (outer shell electrons) get shared between the first and second element in the compound the purpose is for both the elements to get to the stable state by having the outer shell filled up to 8 electrons. See image.
10 inches because at 4 pm it was 6 inches but since it says it increases 4 inches during the times 4 PM through 6 PM it should've gone up another 4 inches. 6 plus 4 equals 10. ?????????
