The radioactive decay of unstable isotopes continually generates new energy within Earth's crust and mantle, providing the primary source of the heat that drives mantle convection. Plate tectonics can be viewed as the surface expression of mantle convection.
Helium which has a chemical formula of He is considered as
a noble gas while Nickel which has a chemical formula of Ni is considered as
metallic. Although both have different phases but they are both classified under
the general category of “Elements”.
Universal indicator can show us how strongly acidic or alkaline a solution is, not just that the solution is acidic or alkaline. This is measured using the pH scale , which runs from pH 0 to pH 14.
