For a1, its atomic number is 13 and its mass number is 27 how many neutrons does it have?

What is the maximum number of electrons that an atomic orbital can contain?

Why is the melting of ice a physical change ?

What effect would average population growth have on land usage? a. urban use of land would rise to more than 30 percent of available land. b. industrial use of land would rise to more than 30 percent of available land. c. the percentage of available land used as cropland would stay the same. d. cropland would fall to about 10 percent of available land.