Crust, Mantle, Core.
Earth's crust is made up of several elements: iron, 32 percent; oxygen,
30 percent; silicon, 15 percent; magnesium, 14 percent; sulfur, 3
percent; nickel, 2 percent; and trace amounts of calcium, aluminum and
The mantle under the crust is about 1,800 miles deep (2,890 km). It is
composed mostly of silicate rocks rich in magnesium and iron.
The core has two parts: the inner core and the outer core which is composed of a nickel-iron alloy.
hope it helped :))