Some basic questions:
1) I can't figure out how two atoms form a covalent bond. We say two atoms make a covalent bond when they share an electron. On the other hand, we know that electrons circulate around the nucleus so fast! For example, one thousand times in a second! So does this "electron sharing" mean that an electron in an atom now circulates 500 times around its own nucleus and 500 times around the nucleus of the other atom?
2) Another question: they say after a covalent bond forms, the probability of finding an electron in the space in the middle of two atoms becomes larger than in other places. But if electrons still circulate around the nucleus, does that mean that now a shared electron mostly orbits the circle that passes through the bonding place? Or does electron motion change, basically?