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131ancient Rome — ▪ ancient state, Europe, Africa, and Asia Introduction the state centred on the city of Rome. This article discusses the period from the founding of the city and the regal period, which began in 753 BC, through the events leading to the… …
132nitrogen group element — ▪ chemical elements Introduction any of the chemical elements that constitute Group Va of the periodic table (see Figure >). The group consists of nitrogen (N), phosphorus (P), arsenic (As), antimony (Sb), and bismuth (Bi). The elements share… …
