- ions that have one or more electrons; have a anions gained negative charge the suffix indicates an –ide polyatomic ions can also form covalently atoms that lose or gain electrons or protons only polyatomic ions can lose or gain protons polyatomic cations = positive charge; polyatomic anions = negative charge an is formed by the attraction between a cation and an anion bond an compound is a substance held together by ionic bonds ionic compounds dissociate into individual ions when dissolved in a polar substance, such as water hydration surrounding the ions with the ends molecules with the opposite (partial) charge – hydrogen bonds weak interactions involving partially (+) charged hydrogen atoms the interaction is with another atom with a partial (-) charge can be within the same (large) molecule, or between molecules hydrogen bonds are common and important in living things forms hydrogen bonds because they are weak, hydrogen bonds are relatively easy to manipulate collectively, hydrogen can be very strong they hold together the two strands of DNA, for example – In aqueous systems (such as living organisms), the typical relative bond strengths are: covalent bond > ionic bond > hydrogen bond Chemical Equations Describe Chemical Reactions Reactants are written on the left Products are written on the an arrow () is used to show the direction the reaction proceeds C6H12O6 + 6 O2 6 CO2 + 6 H2O + Energy double arrows of equal lengths () indicate equilibrium reactions (reactions proceeding simultaneously at equal rates in both directions) N2 + 3 H2 2 NH3 Sometimes, different lengths of double arrows are used to indicate which direction is favored CO2 + H2O H2CO3 Oxidation-Reduction Reactions (redox reactions) Are Common in Biological Systems
anions - ions that have gained one or more electrons; have a negative charge the suffix –ide indicates an polyatomic ions can also form covalently atoms that lose or gain electrons or protons only polyatomic ions can lose or gain protons polyatomic cations = positive charge; polyatomic anions = negative charge an bond is formed by the attraction between a cation and an anion an compound is a substance held together by ionic bonds ionic compounds dissociate into individual ions when dissolved in a polar substance, such as water hydration – surrounding the ions with the ends molecules with the opposite (partial) charge hydrogen bonds weak interactions involving partially (+) charged hydrogen atoms the interaction is with another atom with a partial (-) charge can be within the same (large) molecule, or between molecules hydrogen bonds are common and important in living things forms hydrogen bonds because they are weak, hydrogen bonds are relatively easy to manipulate collectively, hydrogen can be very strong – they hold together the two strands of DNA, for example In aqueous systems (such as living organisms), the typical relative bond strengths are: covalent bond > ionic bond > hydrogen bond Chemical Equations Describe Chemical Reactions Reactants are written on the left Products are written on the an arrow () is used to show the direction the reaction proceeds C6H12O6 + 6 O2 6 CO2 + 6 H2O + Energy double arrows of equal lengths () indicate equilibrium reactions (reactions proceeding simultaneously at equal rates in both directions) N2 + 3 H2 2 NH3 Sometimes, different lengths of double arrows are used to indicate which direction is favored CO2 + H2O H2CO3 Oxidation-Reduction Reactions (redox reactions) Are Common in Biological Systems
chapter2activity.docx