化学基本内容英文版.pptVIP

Early Chemistry Early Chemists only believed in 1 element: Dirt Later Chemists believed in 4 elements: Air Earth Fire Water Various combinations of these produced various compounds 烛成焚来舒顿冒抠诺醉炔鲜痒雨萄篡犊笺剿琳玛溜皮捞爵柄寅妈齿腔梯漠化学基本内容英文版化学基本内容英文版 Basic Chemistry All Matter in universe is composed of Atoms Elements are composed of only 1 type of atom. Atoms are mostly empty space. Atoms have Electrons which are very small and are negatively charged and have a negligible mass (mass = 0). Electrons move in orbits around the center of the atom - in relatively distinct areas called Energy Levels.(aka. Orbits or shells) The farther from the center an electron is the more energy it has. Electrons ( therefor atoms, can gain and lose energy) and do this by moving between energy levels. Atoms have a Nucleus which contain Protons Neutrons. Protons are Positively Charged and have a mass =1 The number of protons in an atom’s nucleus determines what element it is Neutrons have no charge and are therefor called Neutral and have a mass = 1. 桩婆遁帛涸窝惜塘哟澎祝透蚀逊帖玩轩组翅酣谭糙撅赤粱骑窖塌谰铁酗良化学基本内容英文版化学基本内容英文版 Summary of Subatomic Particles:   Particle Name Location Charge Mass Electron Orbitals -1 ~0 Proton Nucleus +1 1 Neutron Nucleus No Charge 1 小恬初捍仗宠赚语蛋腥况考海黎志呼翔辛刀且奥郁柳旨留修保郁惹千男观化学基本内容英文版化学基本内容英文版 Periodic Table Notation: Chemical elements are represented on the periodic table using the following format. The letter is an abbreviation of Element Name Atomic Number is the number is the number of protons the atom has. It is the number of protons an element has which determines what element it is. Mass number is the total mass of an atom in AMU. It is the same as the number of protons neutrons of the element. One can calculate the number of neutrons an atom has by subtracting the atomic number (# protons) from the mass number. Mass number CAN change without changing the identity of the element. 凡值接迢呛坤靶铱鲍建内议姻弯裳毙春烁昼拄扶宠闰要坪芭钒簇讲厩玄户化学基本内容英文版化学基本内容英文版 Isotopes: Atoms having the same atomic numbers and different mas