EASY 10 POINTS!!! Help me please!!?

so i have a chemistry test tomorrow. AND i really need to know some stuff. and don't tell me to go look it up cause i don't have time, so if u could help me please. i will pick a best answer and 10 points too. I need to know what is the use of the following elements: magnesium, mercury, zinc, copper, sulfur, iron, lead, silver, iodine, nitrogen, hydrogen, calcium, and carbon?? Do u get what i'm asking?? like what r they used for?? answers please. thnx.