What element is 1s2 2s2 2p6 3s2 3p6 3d7 4s1

What does the cell nucleus do or, how does it function?

This classification of drug typically changes the brain's chemistry and reduces its ability to create its own endorphins.

Achemist has dissolved a certain substance in water. the chemist knows that more of the substance could be dissolved into the water before it stops dissolving. therefore