Can someone help me from 6 to 14 please

How are the terms group and period used on the periodic table

Using the periodic table, complete the following. element: hydrogen symbol: h₂ molecular weight: g mass of one mole: g/mol

Water is a highly important natural resource. which of these would be the best method to conserve water? a) drinking bottled water b) monitoring the ph of rivers c) treating and re-using wastewater d) testing nitrate levels in groundwater