A single 3s electron in a magnesium atom is shielded by a) the 2s and the 2p electrons only

b) the 1s, 2s, and 2p electrons, along with the other 3s electron

c) the 1s, 2s, and 2p electrons

d) the 1s and 2s electrons only

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.