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This overview explores the formation and characteristics of ionic and covalent compounds. Ionic compounds result from the interaction between metals and nonmetals, where metals lose electrons to form cations and nonmetals gain electrons to create anions, resulting in structures like Na2S and (NH4)2S. In contrast, covalent compounds form from nonmetals sharing electrons, exemplified by water molecules. Key properties include high melting points, brittleness, and ionic conductance in solution. Electronegativity is discussed in relation to bond polarity and ionic character.
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Ionic Compounds • made by combination of metal and nonmetal • metal loses electrons – forms cation • nonmetal gains electrons – forms anion • consider Na and S • Na+ and S2- ions formed • pack together to make compound Na2S
Ionic Compounds • can contain polyatomic ions • like (NH4)+ • consider (NH4) + and S2- ions formed • pack together to make compound (NH4)2 S +
Properties of Ionic Compounds • high melting point • hard but brittle • cleave with flat edges • when dissolve in water, dissolves as ions • Conductors when melted or dissolved in water
Covalent (Molecular) Compounds • made by combination of nonmetals only • made by “sharing” electrons • make molecules…fundamental particle of compound
are electrons shared equally? Pure and Polar Covalent Bonds H – H and F - F pure covalent bond H - Cl polar covalent bond
Electronegativity and Bonds • Using electronegativities, arrange the following bonds in order of increasing polarity and identify the shift of the electrons: C – N, O – H, and H – Cl.
Electronegativity and Bonds • Without using the numbers in the electronegativity scale, determine which would be more ionic LiF or BF3?