Why are atoms of carbon-14(C-14) unstable?

What is the formula for the compound dinitrogen pentoxide? a. n4o5 b. n5o4 c. n4o6 d. n5o2 e. n2o5

Solutions of sodium carbonate and silver nitrate react to form solid silver carbonate and a solution of sodium nitrate. a solution containing 3.50 g of sodium carbonate is mixed with one containing 5.00 g of silver nitrate. how many grams of sodium carbonate, silver nitrate, silver carbonate, and sodium nitrate are present after the reaction is complete?

What are the first two quantum numbers for the electrons located in subshell 4d? what are the first three quantum numbers for the electrons located in subshell 2s? how many electrons can be held in a sublevel l = 3? how many electrons can be held in the energy level n = 4? how many electrons in an atom can share the quantum numbers n = 4 and l = 3?