Comparing Types of Bonding Ionic, Covalent, & Metallic

Substance Examples Ionic Covalent Metallic Table salt, NaCl Epsom salt, MgSO4*7H20 Minerals: Find the names and formulas of 20 mineral compounds H2O, CO2, CH4, NH3, sugar, organic compounds, bio chemicals, plastics Metals! Al, Fe, Cu, Ag, Au! Alloys like brass & steel

Element Composition Ionic Covalent Metallic Metals (M) combined with non-metals (N) (M+)(N-) Non-metals with non-metals N-N Metals! M

M+ N- How they Bond M+ Ionic Covalent Metallic Opposite charges attract! (How do ions form?) Atoms share electrons to complete stable valence shells. Atoms share electrons communally! M+ O M+ N- H H

Physical State & Strength Ionic Covalent Metallic Crystals – opposites charges organize. Brittle – upsetting opposite charges results in breakage. Solids, liquids, gases. Wide variety of properties. Crystalline – atoms arranged as simple as possible. Malleable – communal sharing can adjust as atoms move.

Solubility & Conductivity Ionic Covalent Metallic Often water soluble – polar water molecules will surround and separate (+) & (-) charges = dissociation Electrolytes – (+) & (-) charges can migrate when dissolved. Soluble in water if polar like alcohol. Insoluble in water if nonpolar like oil. Molecules are non-conductive – electrons are shared tightly and can’t flow. Very little solubility in water. Highly Conductive Communal electrons can flow in an electric field.

Chemical Properties Ionic Covalent Metallic Precipitate – Insoluble combinations combine to form crystals that water can’t dissolve. Ion Rxns Lab formed cloudy precipitates. Wide variety of reactions. Corrode – easily lose electrons (oxidized) to form (+) ions and often dissolve away. Example: Rust!

Communal sharing of electrons will adjust with changing shape Why are transition metals like iron so strong? M+ M+ Back

M+ N- N- M+ Ionic bonding requires alignment of opposite charges. Shifting charges will break it! N- M+ M+ N- Back

Electricity http://faraday.physics.utoronto.ca/IYearLab/Intros/DCI/Flash/WaterAnalogy.html http://www.thetech.org/exhibits/online/topics/13a_flash.html