Identify each of the following as either an element or Compound. Write (E) for Element and (C) for compound.

a. carbon
b. water
C. aluminum foil
d. plastic
e, tin
f. silicon dioxide
g. helium
h, arsenic
i. carbon dioxide
j. sodium chloride (table salt)

Significant figures are digits read directly from the measuring instrument plus one more digit, which is __ by the observer.

I'm learning about the periodic tables and what each subject's configuration is. for example, hydrogen is 1s^1, but i don't understand how you get that. can someone me understand how to figure out how to figure this out? sorry if the question makes no sense, but it would really a lot if you could me understand! you so much if you can!

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