What happens to the composition of an atom to cause it to become positively or negatively charged?

Noble gases are the most reactive elements on the periodic table. a. true b. false

Arectangle has a diagonal 20 inches long that forms angles of 60 and 30 with the sides. find the perimeter of the rectangle. for geometry

Calculate the partial pressure, in atmospheres, of o2 in the dry air outside an airliner cruising at an altitude of about 20000 ft (6096 m), where the atmoshperic pressure is 351 mm hg. how much must the outside air be compressed to produce a cabin pressure in which the partial pressure of o2 is 0.200 atm?