If an atom gains or loses an electron it tends to become what?

Joan writes four numbers on the board in standard form, and then she writes their scientific notation

What woukd most likely be the transmittance at a 0.70 m solution of solute a? a) 7.6%b) 1.1%c)4.0%d)4.6%

Iron (3) oxide will decompose in the presence of hydrogen gas and heater to produced iron and digydrogen monoxide white a balanced chemical equation