Palladium │Pd │ 106.6 Phosphorus │P │ 31 Platinum │Pt │ 195 Potassium │K │ 39.11 Praseodymium│Pr │ 143.5 Rhodium │Rh │ 103 Rubidium │Rb │ 85.5 Ruthenium │Ru │ 101.6 Samarium │Sm │ 150 Scandium │Sc │ 44 Selenium │Se │ 79 Silicon │Si │ 28.4 Silver │Ag │ 107.92 Sodium │Na │ 23.05 Strontium │Sr │ 87.6 Sulfur │S │ 32.06 Tantalum │Ta │ 182.6 Tellurium │Te │ 125 Terbium │Tb │ 160.0 Thallium │Tl │ 204.18 Thorium │Th │ 232.6 Thulium │Tu │ 170.7 Tin │Sn │ 119 Titanium │Ti │ 48 Tungsten │W │ 184 Uranium │U │ 239.6 Vanadium │V │ 51.4 Ytterbium │Yb │ 173 Yttrium │Yt │ 89.1 Zinc │Zn │ 65.3 Zirconium │Zr │ 90.6 ────────────┴───────┴─────── Footnote A: Has priority over niobium. Footnote B: Has priority over beryllium. Footnote C: Standard or basis of the system. PROPERTIES OF THE ELEMENTS. Following is a brief description of the most important elements occurring in the earth’s crust in respect of their relations to agriculture.