Osteoarthritis is by far the most common form of arthritis, affecting about 16 million Americans, while rheumatoid arthritis, which affects about 2.1 million Americans, is the most crippling form of the disease.
Most Abundant Metal in the Earthâs Crust. Aluminium â Itâs the most abundant metal in the Earthâs crust, yet it entirely escaped our notice until 1825. You might say it was hidden in plain sight. Aluminium is a highly reactive metal, meaning it readily undergoes chemical reactions with other elements and compounds to form different substances.
The mass-abundance of the nine most abundant elements in the Earth's crust (see main article above) is approximately: oxygen 46%, silicon 28%, aluminum 8.2%, iron 5.6%, calcium 4.2%, sodium 2.5%, magnesium 2.4%, potassium, 2.0%, and titanium 0.61%.ydrogen is the most abundant element in the Universe; helium is second. However, after this, the rank of abundance does not continue to correspond to the atomic number; oxygen has abundance rank 3, but atomic number 8. All others are substantially less common.