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Atomaire bindingen - ionische binding - covalente binding - metallische binding.

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Presentation on theme: "Atomaire bindingen - ionische binding - covalente binding - metallische binding."— Presentation transcript:

1 Atomaire bindingen - ionische binding - covalente binding - metallische binding

2 Ionic bonding 1 E between a Li atom and a F atom

3 Ionic bonding 2 E gives Li + F - molecule Ionization Potential (IP) Electron Affinity (EA) Energy cost:  E = IP(Li) – EA(F)

4 Ionic bonding 3 Ionic binding curve: electron transfer Coulomb attraction ions Pauli repulsion Binding curve has stable minimum !!

5 Ionic bonding 4 only works between very dissimilar atoms !!

6 Ionic bonding in solids NaCl structureCsCl structure Na + Cl - Cs + common salts have ionic bonding structure determined by relative size ions

7 Covalent bonding 1 Model system: one electron in two wells wells far apart wells close ES < EAES < EA electron wants to pull wells close !!

8 Covalent bonding 2 H 2 molecule: two electrons in two wells E H atom H 2 molecule allowed by Pauli

9 Covalent bonding 3 He 2 molecule? four electrons E He atom He 2 molecule  no electronic bonding in He 2  no stable He 2 molecule !!  because of Pauli exclusion principle

10 Hetero-atomic covalent bonding E H F molecule polar bond !! H atomF atom

11 Poly-atomic covalent bonding 1 H 2 O molecule 2 2 covalent bonding gives directional bonds !!

12 Poly-atomic covalent bonding 2 CH 4 molecule: tetraeder C hybrid orbital

13 Covalent bonding in solids C, Si,... have covalent bonding diamond structure and compound semiconductors: GaAs,...

14 Metallic bonding in solids 1 positive ions metal: one electron in many wells has a wave-like character (delocalized)

15 'Fermiology'

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26 Twee verschillende metalen met elkaar in contact  contact-potentiaal

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28 Volgende (laatste) hoor-college: Quantum theorie van electrische geleiding Isolatoren vs. (half)geleiders, supergeleiders Terugblik op de gehele stof


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