IB DP Chemistry: HL复习笔记14.2.2 Ozone Revisited
Ozone Revisited We have seen previously that ozone is a molecule with two resonance structures leading to a resonance hybrid The two Lewis resonance structures for ozone The central oxygen atom has...
IB DP Chemistry: HL复习笔记14.2.1 Delocalisation & Resonance
Delocalisation & Resonance The delocalisation of electrons can explain the structures of some species that don’t seem to fit with a Lewis structure Delocalised electrons are electrons in a mole...
IB DP Chemistry: HL复习笔记14.1.4 Formal Charge
Formal Charge A limitation of the model of covalent bonding is that when drawing Lewis structures for molecules, it is sometimes possible to come up with more than one structure while still obeying...
IB DP Chemistry: HL复习笔记14.1.3 Further VSEPR Theory
Further VSEPR Theory Revisiting Valence Shell Electron Pair Repulsion Theory (VSEPR) When an atom forms a covalent bond with another atom, the electrons in the different bonds and the non-bonding e...
IB DP Chemistry: HL复习笔记14.1.2 More Lewis Structures
Octet Rule Exceptions Incomplete octets We have seen previously that for elements below atomic number 20 the octet rule states that the atoms try to achieve 8 electrons in their valence shells, so ...
IB DP Chemistry: HL复习笔记14.1.1 Covalent Bonds
Sigma Bonds Bond overlap in covalent bonds A single covalent bond is formed when two nonmetals combine Each atom that combines has an atomic orbital containing a single unpaired electron When a cov...
IB DP Chemistry: HL复习笔记13.1.6 Factors Affecting Colour
Factors Affecting Colour The size of the splitting energy ΔE in the d-orbitals is influenced by the following four factors: The size and type of ligands The nuclear charge and identity of the metal...
IB DP Chemistry: HL复习笔记13.1.5 Colour in Transition Metals
Crystal Field Theory Perception of colour Most transition metal compounds appear coloured. This is because they absorb energy corresponding to certain parts of the visible electromagnetic spectrum ...
究竟哪一个才是最具权威的世界大学排名？
关于大学排名信息不实早已不是鲜见的新闻，每一次各大世界大学排行榜一发布，总是会引发各路人士激烈的讨论。有人乐于分享自己学校的好成绩，也有人怒于声讨和质疑排名的准确性。那这五花八门的各大排行榜单中，...
