Magnesium
Orbital Notation: Electron Configuration

Infants born with severe respiratory problems are sometimes given liquid ventilation: they breathe a liquid that can dissolve more oxygen than air can hold. one of these liquids is a fluorinated compound, cf3(cf2)7br. the solubility of oxygen in this liquid is 66 mlo2 per 100 ml liquid. in contrast, air is 21 % oxygen by volume. calculate the moles of o2 present in an infant's lungs (volume: 12 ml ) if the infant takes a full breath of air. assume a pressure of 1 atm in the lungs.

Iknow the answer is a but i don't know why

Compare and contrast physical changes with chemical changes.