Based on this cell from the periodic table, which statement is true for the element magnesium?

A. A magnesium atom contains 12 protons, and neutral magnesium
atoms contain 24 electrons.
B. A magnesium atom contains 12 protons, and most magnesium
atoms contain 12 neutrons.
C. The atomic number of magnesium is 24.3, and its atomic mass is
12
D. The atomic number of magnesium is 12, and its average atomic
mass is 12

Consider an ordinary, helium-filled party balloon with a volume of 2.2 ft3. the lifting force on the balloon due to the outside air is the net resultant of the pressure distribution exerted on the exterior surface of the balloon. using this fact, we can derive archimedes’ principle, namely that the upward force on the balloon is equal to the weight of the air displaced by the balloon. assuming that the balloon is at sea level, where the air density is 0.002377 slug/ft3, calculate the maximum weight that can be lifted by the balloon. note: the molecular weight of air is 28.8 and that of helium is 4.

** urgent** the voltage across the primary winding is 350,000 v, and the voltage across the secondary winding is 17,500 v. if the secondary winding has 600 coils, how many coils are in the primary winding? a- 30 coilsb- 583 coilsc- 12,000 coilsd- 332,500 coils

What does the law of conservation of mass state?