What is in the center of an atom? what is this portion of the atom called?

*will mark you brainliest + 15 points ** why does the equilibrium of a system shift when the pressure is increased? a. to maximize the stress on the system b. to stop restoring equilibrium to the system c. to increase the total moles of gas in the system d. to decrease the total moles of gas in the system

Joan writes four numbers on the board in standard form, and then she writes their scientific notation

How many moles are in 43.9 l of oxygen