Period 6 element between barium and hafnium, and radium and rutherfordium, respectively. This convention is entirely a matter of aesthetics and formatting practicality; a rarely used wide-formatted periodic table inserts the lanthanide and actinide series in their proper places, as parts of the table's sixth and seventh rows (periods). Lanthanum is a chemical element with the symbol La and atomic number 57. It is the first element in the lanthanide series. It is a soft, ductile, silvery-white metal that tarnishes rapidly when exposed to air and is soft enough to be cut with a knife. It is the eponym of the lanthanide series,
Metallic dragon and adamantine dragons for brass and bronze, and released the latter dragons in a later book alongside cobalt, mercury, mithral, orium, and steel dragons. The classification of "metallic dragons" was used in the "Advanced Dungeons & Dragons" second edition "Monstrous Manual" (1993), although the gold(en) dragon first appeared in the original "Dungeons & Dragons" "white box" set (1974) and the other dragons comprising the category had been in print since the first edition "Monster Manual" (1977). The term was continued in use in the third edition and fourth edition "Monster Manual". Although weaker than many other varieties of dragonkind, brass