How do you determine the number of electrons in an atom

What royal scientist used the 29th day of frozen vapor to encounter elements for mastering new culinary creations?

Which of the following are correct values for the ideal gas laws constant r

A4.86 g piece of metal was placed in a graduated cylinder containing 15.5 ml of water. the water level rose to 17.3 ml. what is the density of the metal. i need the steps of how to solve it to so i can use a formula to work out other problems.