How many molecules are in 12.5g of water
(H2O)?
Molar mass
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1) how many electrons are in each energy level of the following elements? a. he b. na c. na d. ne 2) how many valence electrons are percent in the following atoms? a. s b. mg c. be d. cl 3) which of the following elements are stable as atoms? a. he b. o c. cl d. ar if you are able to provide the work as to how you got the answers that would be greatly appreciated. : )

Stoichiometry- i need with 14 and 15! an explanation would be appreciated!

Agust of wind blowing east pushes against a ball. when will the wind do work on the ball? when the ball moves to the east when the ball moves to the north when the ball stays in one place when the ball moves north or south