How do i do this if carbon has 4 valence electrons and oxygen has six valance electrons how do i do that if they only need eight valance electrons

Compare the valence electron configuration of the nobles gas elements seen here. what statement is correct?

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.

12. calculate the hydroxide ion concentration of a solution with ph = 3.25. show all calculations leading to an answer