In term of electron and energy level what the electron configurations 2-8-1 really mean

How many moles of al3+ ions are in 1.25 moles of al2o3

When balancing a chemical equation:

Skills of homo sapiens were found an excavation. the skulls were preserved because the bodies were frozen. so, these fossils are (blank) fossils.the image shows the evolution of skulls beginning 2 to 3 million years ago. based on the image, modern human skulls(blank) ape skulls.