Bonding Atoms come together in one of 3 principle types of bond Ionic and ions charged atoms joined by an electrostatic interaction Covalent Sharing of electrons equally between ions Metallic sharing of electrons between many atoms O2 NaCl Ionic vs Covalent Elements on the right and top of the periodic table draw electrons strongly Bonds between atoms from opposite ends more ionic diatomics are 100 covalent Bond strength Covalent Ionic metallic Affects hardness melting T solubility Bond type affects geometry of how ions are arranged More ionic vs covalent higher symmetry Metallic Bonds Electron sharing can go in any direction results in more malleable material Also affects electronic properties metallic materials conduct electricity better Affects redox reactions where there is a transfer of electrons as a part of dissolution electrons are nonbonding or delocalized which makes materials less polar and thus less soluble is water Bond Character Other types of bonding Van der Waals Interaction between molecular units which assemble a mineral from weak electrostatic interactions Hydrogen H bonds molecular subunits together Dative special type of covalent bond all bonding electrons donated by one ion Ionic bonding Most common minerals on earth are composed of ionic bonds Covalently bonded anionic subunits are often ionically bonded to cations to form these minerals SiO44 CO32 PO43 SO42 Mineral properties are more often compared by the anionic component thus most classification schemes focus on this Ionic vs Covalent Bond strength Covalent Ionic metallic Affects hardness melting T solubility Bond type affects geometry of how ions are arranged More ionic vs covalent higher symmetry Ionic bonding Most common minerals on earth are composed of ionic bonds Covalently bonded anionic subunits are often ionically bonded to cations to form these minerals SiO44 CO32 PO43 SO42 Mineral properties are more often compared by the anionic component thus most classification schemes focus on this Nesosilicates SiO44Sorosilicates Si2O76 Cyclosilicates Si6O1812 Inosilicates single Si2O64 Inosilicates double Si4O116 Phyllosilicates Si2O52 Tectosilicates SiO20 How many molecules Pyrite FeS2 Would there be any other elements in there Bangledesh groundwater Most severe arsenic problem in the world Shallow wells installed Area 147 570 km2 Population 128 million people Natural source of Arsenic WHO drinking standard 10 ug L Bangladesh standard 50 ug L 97 drinking water is contaminated 80 of population at risk to poisoning
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