Fundamentals of Chemistry DOE-HDBK-1015/1-93 THE PERIODIC TABLE Rev. 0        CH-01 Page 13 TABLE 3 (Cont.) Description of the Properties of the First Twenty Elements Lithium Li 3 6.939 Silvery white, soft metal, very reactive chemically, forms Li O and 2 LiCl readily. Beryllium Be 4 9.012 Grey metal, much harder than lithium, fairly reactive chemically, forms BeO and BeCl  easily. 2 Boron B 5 10.811 Yellow or brown non-metal, very hard element, not very reactive, but will form B O , and BCl 2 3 3 Carbon C 6 12.011 Black non-metal, brittle, non-reactive at room temperature. Forms CO  and CCl . 2 4 Nitrogen N 7 14.007 Colorless gas, not very reactive, will form N O  and NH . 2 5 3 Oxygen O 8 15.999 Colorless gas, moderately reactive,will combine with most elements, forms CO , MgO, etc. 2 Fluorine F 9 18.998 Green-yellow gas, extremely reactive, irritating to smell, forms NaF, MgF .₂ Neon Ne 10 20.183 Colorless gas, very non-reactive chemically. Sodium Na 11 22.990 Silvery soft metal, very reactive chemically, forms Na O and NaCl. 2 Magnesium Mg 12 24.312 Silvery white metal, much harder than sodium.  Fairly reactive, forms MgO and MgCl .₂ Aluminum Al 13 26.982 Silvery white metal, like magnesium but not as reactive.  Forms Al O  and AlCl . 2 3 3 Silicon Si 14 28.086 Gray, non-metallic, non-reactive at room temperature, forms SiO₂ and SiCl .₄ Phosphorus P 15 30.974 Black, red, violet, or yellow solid, low melting point, quite reactive, forms P O  and PCl . 2 5 3 Sulfur S 16 32.064 Yellow solid with low melting point.  Moderately reactive, combines with most elements, forms SO , MgS, etc. 2 Chlorine Cl 17 35.453 Greenish-yellow gas, extremely reactive, irritating to smell, forms NaCl, MgCl .₂ Argon Ar 18 39.948 Colorless gas, very non-reactive chemically. Potassium K 19 39.102 Silver soft metal, very reactive chemically, forms K O and KCl. 2 Calcium Ca 20 40.080 Silver-white metal, much harder than potassium, fairly reactive, forms CaO and CaCl .₂