Question: what are the two most abundant elements by mass found in earth's crust
Answer: Abundance of chemical elements in Earth 's crust , from various sources Rank Z , element & symbol Abundance in crust ( ppm ) by source Annual production Darling Barbalace WebElements Israel Science and Technology Jefferson Lab ( 2016 , tonnes ) 8 oxygen 466,000 474,000 460,000 467,100 461,000 14 silicon Si 277,200 277,100 270,000 276,900 282,000 7,200,000 13 aluminium Al 81,300 82,000 82,000 80,700 82,300 57,600,000 26 iron Fe 50,000 41,000 63,000 50,500 56,300 1,150,000,000 5 20 calcium Ca 36,300 41,000 50,000 36,500 41,500 6 11 sodium Na 28,300 23,000 23,000 27,500 23,600 255,000,000 7 19 potassium 25,900 21,000 15,000 25,800 20,900 8 12 magnesium Mg 20,900 23,000 29,000 20,800 23,300 1,010,000 9 22 titanium Ti 4,400 5,600 6,600 6,200 5,600 6,600,000 10