Structure 2.4

• Lattice Enthalpy

  A measure of the strength of electrostatic attraction between ions in a compound- it is inversely proportional to the molecule's radii and directly proportional to its charge (in absolute value)
• Naming Binary compounds


  Whole name of the metal + root of the basic name + "ide"

  ex. Sodium chlor -ide
• Naming transition metals

  Taking its charge as its roman value

  ex. Cr^3+ = Chromium (III)
• Combining Polyatomic ions

  "Swap and drop" their charges

  ex. 3(NH4), (PO4)^3- -> (NH4)3 PO4

  because 3 is PO4's charge transferred to NH4, and 1 is NH4's charge, transferred to PO4
• Bonding can be viewed as a continuum meaning it has properties on the boundaries between different intramolecular forces
• The simplest ration of ions is often sourced through the "swap and drop" method
• Formula units

  Ionic bonds between two oppositely charge molecules part of a crystal lattice

  
• London Dispersion Forces


  Weakest force that is present more strongly in larger atomic molecules with great atomic numbers and non-polar substances. Often has rapidly fluctuating dipoles that can be influenced by greatly polar molecules to prompt dipole-induced-dipole forces
• Dipole Dipole forces

  Establishment of opposite charges at either end of the molecule; increases with higher polarity. The delta positive dipole is at the molecule with lower electronegativity than then other, where the delta negative dipole is posed
• Hydrogen bonding


  Strongest intermolecular force that occurs upon Hydrogen's bonding with either Oxygen, Nitrogen, or Fluorine because they all have lone pairs of electrons they can bind to Hydrogen with and H's great positive charge is attracted to its negativity
• Effective nuclear charge (Combined expansionary and contractionary effect)

  Nuclear charge - Shielding effect
• Nuclear charge

  The pull of the nucleus' positive charge to the electrons- greater number of protons = greater nuclear charge = smaller atomic radii (contractionary effect)
• Shielding effect

  Repulsion of valance electrons by inner electrons- greater ratio of inner : valance = higher shielding effect = larger atomic radii (expansionary effect)
• All metals have luster due to their delocalized electrons (which are innately reflective)
• Biological macromolecules

  Naturally occurring polymers that take a long time and much difficulty to break down through hydrolysis due to its complex structures
• Crystalline solids

  Highly ordered lattice extending in all directions tied through covalent and ionic bonding, usually (ex. salt, sugar, dimond) or sometime, metallic bonding (Bismoth metal)
• Polar solutes can only dissolve in polar solvents and vise versa as they need to overcome bond strengths of solvents to dissolve
• Model non-polar solvent

  Hexane
• Model polar solvent

  Water
• Covalent character

  With an electronegativity between 0 and 0.4- the higher the value in that range, the stronger the character
• Ester link

  Between a Hydroxyl (Alcohol) and Carbonyl (Kentones) functional group
• Condensation polymers


  Formed by the reaction between monomers causing the release of a small molecule
• Functional groups

  A group of atoms that give physical and chemical properties to compounds
• Condensation polymerization of monomers

  Create bi-products of small molecules- never big molecules like propanoic acid
• Impurities

  Decrease malleability as layers cannot slide over each other as easily as before due to their space being impaired with the addition of another element
• Why are Lewis structures always angled a certain way

  Presence of lone pairs add extra pull or push that change and influence its structure
• Structural formulas for polymers are often condensed like follows;

  
• From metals to alloys

  Decrease in malleability as new sizes within the lattice make it harder to shift; Decrease in melting point as lower electrostatic attraction is present (relative to percentage composition)
• Strength of a metallic bond

  -> comes with smaller radii making a stronger bond with a shorter distance between the cations and electrons

  -> higher charge of the metal increasing bond strength with increased attraction

  -> increased density increases bond strength with increased attraction

  -> melting points are higher as bonds are stronger (consistent down a group)

  -> hardness is increased with bond strength as there is less space and the tension is high
• Hardness


  A measure of a material's resistance to deformation
• Metals

  Have luster, propagate sound waves due to their high density, are malleable and ductile due to non-directional bonding, are electrically and thermally conductive due to the ability to move charged particles.
• Ester links

  The linking of 2 hydrocarbon groups with oxygen and ALWAYS present in polyester bonds
• Dipole-induced-dipole force

  Non-polar molecule is influenced to form temporary dipoles with the presence of a very polar molecule. Increase in effect with proximity to the polar molecule and largeness of non-polar molecule due to its electron's distance from the nucleus making it more prone to other attractions
• Metallic bonding

  Positive, fixed, metal ions in a tight lattice attracting negative, free-flowing, delocalized electrons throughout the structure creating an overall neutral charge with cations' positive and electrons' negative. The strength of the bond is increases with a greater amount of valance electrons in the reactants of the bond, smaller radii of the cation, and higher charge of the cation