Group 7: Physical Properties The group 7 elements are called?halogens The halogens have uses in water purification and as bleaching agents (chlorine), as flame-retardants and fire extinguish...
Group 2: Trends Chemical trends All elements in Group 2 (also called?alkali earth metals)?have two electrons in their?outermost principal quantum shell All Group 2 metals can form?ionic?compounds?i...
The Periodic Table: Structure & Classification The?periodic table?is a list of all known elements arranged in order of?increasing atomic number,?from 1 to 118. In addition to this, the elements...
Oxidation & Reduction There are three definitions of?oxidation?and?reduction? used in different branches of chemistry Oxidation?and?reduction?can be used to describe any of the following proces...
Reversible Reactions & Dynamic Equilibrium Reversible reaction Some reactions go to completion where the reactants are used up to form the products and the reaction stops when all of the reacta...
Collision Theory Collision theory The?collision theory?states that for a chemical reaction to take place the particles need to?collide?with each other in the correct?orientation?and with enough?ene...
英國教育可以分兩個系統(tǒng)：公立教育和私立教育。這兩種教育主要區(qū)別在于， 公立教育系統(tǒng)里學校的財政開支和管理由中央政府或者當?shù)卣M行管控。大部分公立學校為走讀學校， 全英共有39所公立寄宿制學校， 但這些...
USACO 美國計算機奧林匹克學術(shù)活動 United States of America Computing Olympiad 簡稱USACO，USACO學術(shù)活動是美國最具認可度的計算機學術(shù)活動，用于選拔美國參加全球信息奧林匹克學術(shù)活動（IOI）的國家隊，學術(shù)...
Bond Energy During a reaction, enthalpy changes take place because bonds are being broken and formed Energy (in the form of heat) is needed to overcome attractive forces between atoms Bond breaking...
