Ejercicio
-Nombrar los siguientes compuestos e indicar a que clase de compuestos pertenecen. Escribir la ecuación de formación de cada uno y su estructura de Lewis.
NaCl
H2O
KF
Na2O
K2O
MgO
CaO
Al2O3
Teoría de Química, Física y Matemática
NaCl
H2O
KF
Na2O
K2O
MgO
CaO
Al2O3
Ionic Compounds
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Covalent Compounds
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You can anticipate some things about bonds from the positions of the constituents in the periodic table. Elements from opposite ends of the periodic table will generally form ionic bonds. They will have large differences in electronegativity and will usually form positive and negative ions. The elements with the largest electronegativities are in the upper right of the periodic table, and the elements with the smallest electronegativities are on the bottom left. If these extremes are combined, such as in RbF, the dissociation energy is large.
FUENTE: http://hyperphysics.phy-astr.gsu.edu/Hbase/chemical/bond2.html
· Electrical conductivity of the compound in aqueous solution. Ionic compounds conduct electricity when dissolved in water, because the dissociated ions can carry charge through the solution. Molecular compounds don't dissociate into ions and so don't conduct electricity in solution.
· Electrical conductivity of the compound in liquid form. Ionic compounds conduct electricity well when melted; metallic solids do as well. Covalent molecular compounds do not, because they usually don't transfer electrons unless they react.
· Hardness. Molecular solids are usually much softer than ionic materials. Ionic crystals are harder but often quite brittle. Squeezing an ionic crystal can force ions of like charge in the lattice to slide into alignment; the resulting electrostatic repulsion splits the crystal.
· Melting points and boiling points. In an ionic compound, the forces of attraction between positive and negative ions are strong and high temperatures are required to overcome them. The melting and boiling points of ionic compounds are usually very high. A smaller amount of energy is required to overcome the weak attractions between covalent molecules, so these compounds melt and boil at much lower temperatures than metallic and ionic compounds do. In fact, many compounds in this class are liquids or gases at room temperature.
FUENTE: http://antoine.frostburg.edu/chem/senese/101/compounds/faq/properties-ionic-vs-covalent.shtml