The diagram shows the electron arrangement in 4 elements, Pls select one

Here there is an attachment, look into that* pls ASAP

6. using 3 – 4 sentences explain (in your own words) why water expands when it freezes? 7. using your knowledge of colligative properties explain whether sodium chloride or calcium chloride would be a more effective substance to melt the ice on a slick sidewalk. use 3 – 4 sentences in your explanation.