Which of the following elements is a metal?
a. boron
c. magnesium
b. nitrogen
d. carbon select the best answer from the choices provided a b c d?

11. phosphorus-32 is radioactive and has a half life of 14 days. how much of a 124 mg sample of phosphorus-32 is present after 56 days? a) 7.75 mg b) 15.5 mg c) 31.0 mg d) 62.0 mg

Chlorophyll a had the molecular formula c55h72mgn4o5 how many atoms are in this molecule

Is this correct if not can u correct me