AP课程 VS NEC，2022NEC全美经济学挑战赛报名中！
NEC全美经济学挑战（National economic challenge）由美国经济教育学会举办的经济学学术活动。它是美国最负盛名、最具影响力的中学生经济学学术活动。AP课程 VS NEC，2022新赛季报名中！ NEC的知识体系与多种主要...
Edexcel A Level Chemistry:复习笔记1.2.4 Electronic Configurations
Electronic Configurations of Atoms & Ions The principal quantum shells increase in energy with increasing principal quantum number E.g. n = 4 is higher in energy than n = 2 The su...
Edexcel A Level Chemistry:复习笔记1.2.3 Orbitals
Orbital Shapes Orbitals Subshells contain one or more atomic orbitals Orbitals exist at specific energy levels and electrons can only be found at these specific levels, not in between them E...
Edexcel A Level Chemistry:复习笔记1.2.2 Quantum Shells
Developing Electronic Configuration Electrons move rapidly around the nucleus in energy shells If their energy is increased, then they can jump to a higher energy level The process is revers...
Edexcel A Level Chemistry:复习笔记1.2.1 Ionisation Energy
Factors Affecting Ionisation Energy Ionisation energy The ionisation Energy (IE) of an element is the amount of energy required to remove one mole of electrons from one mole of gaseous atoms...
Edexcel A Level Chemistry:复习笔记1.1.4 Mass Spectrometry
Interpreting Mass Spectra Isotopes are different atoms of the same element that contain the same number of protons and electrons but a different number of neutrons These are atoms of the sam...
Edexcel A Level Chemistry:复习笔记1.1.3 Relative Mass
Isotopic & Atomic Mass The relative mass of an atom uses the carbon-12 isotope as the international standard One atom of carbon-12 has an accepted mass of 1.992646538 x 10-26 kg It is not reali...
Edexcel A Level Chemistry:复习笔记1.1.2 Isotopes
Atomic Structure Calculations An atom is neutral and has no overall charge Ions on the other hand are formed when atoms either gain or lose electrons, causing them to become charged The numb...
Edexcel A Level Chemistry:复习笔记1.1.1 Structure of the Atom
Structure of the Atom All matter is composed of atoms, which are the smallest parts of an element that can take place in chemical reactions Atoms are mostly made up of empty space around a v...
