Most nitrogen atoms have seven protons and seven neutrons, so their atomic mass is 7 7 = 14.
Most carbon atoms have six positively charged protons and six uncharged neutrons.In recent years batteries have changed out of all recognition. Today the cells are components in battery systems, incorporating electronics and software, power management and control systems, monitoring and protection circuits, communications interfaces and thermal management. Mesopotamia, incorporating Sumer, Babylonia and Assyria, known in the West as the Cradle of Civilisation was located between the Tigris and Euphrates rivers (The name means "land between the rivers") in the so called Fertile Crescent stretching from the current Gulf of Iran up to modern day Turkey. the Sumerians of ancient Mesopotamia developed the World's first written language.(See Map of Mesopotamia) Unfortunately this accolade ignores the contributions of the Chinese people and the Harappans of the Indus Valley, (Modern day Pakistan) who were equally "civilised" during this period practicing metallurgy (copper, bronze, lead, and tin) and urban planning, with civic buildings, baked brick houses, and water supply and drainage systems. Called Cuneiform Writing from the Latin "cuneus", meaning "wedge", it was developed as a vehicle for commercial accounting transactions and record keeping.Three of the Carbon isotopes (C) are found in nature.The rest of the carbon isotopes are only of laboratory interest.