How many distinct and degenerate p orbitals exist in the second electron shell, where n = 2?

Describe the difference between a. a hypothesis and a theory and b. an observation and an experiment.

Which is a chemical property of iron? a. it forms iron oxide (rust) when exposed to moisture and air. b. it is a gray–black metal that is hard to the touch. c. it has a melting point of 2795°f (1536°c). d. it is a good conductor of heat

Which of the following units is not an official si unit? mole liter kilogram ampere