Which rule for assigning oxidation numbers is correct?
O Hydrogen is usually - 1
O Oxygen is usually -2.
O Apure group 1 element is +1.
O Amonatomic ion is 0.

why is arctic sea ice important? arctic sea ice keeps the polar regions cool and moderate global climate. sea ice has a bright surface; 80 percent of the sunlight that strikes it is reflected back into space. as sea ice melts in the summer, it exposes the dark ocean surface.