Ionic Bonding

Ion- a charged particle, (when particles lose/gain electrons)

cation- positive ion (lost electrons, metals)

anion- negative ion (gained electrons, nonmetals)

Group 14- don't generally gain or lose 4 electrons, don't usually form ionic compounds

Transition elements- form different ions

Why do transition elements form different ions- electron configuration allows them to lose different number of elements from d subshell

­ ionization - where electrons are transferred between atoms ­ oppositely charged ions result

what are oppositely charged ions held together by- electrostatic forces (ionic bonds)

charge of ionic compounds- electrically neutral

Quantum Numbers - Chemistry Steps

Ionic Compounds have a Lattice Structure ­

ionic lattice - predictable 3D crystalline structure, fixed arrangement of ions based on a repeating unit ­

coordination number - number of ions that surround a given ion in the lattice (NaCl lattice, the coordination number is 6 because each Na + ion is surrounded by 6 Cl ­ ions and each Cl ­ ion is surrounded by 6 Na + ions) ­

lattice energy ­- measure of the strength of attraction between the ions within the lattice

lattice energy for smaller ions- (greater for ions that are small and highly charged, as they have a larger charge density)

la

The Physical Properties of Ionic Compounds Reflect Their Lattice Structure

  • tend to have high melting and boiling points as the forces of electrostatic attraction between the ions in the lattice are strong and so require lots of energy to break ­

  • solids at room temperature ­

  • volatility ­

    • tendency of a substance to vaporize ­

  • low volatility

  • ­low odour ­

  • easily hydrated (ions are surrounded by water molecules)

  • ­ ionic compounds are generally soluble in ionic polar solvents but not soluble in non­polar solvents ­

  • dissolved in something other than water, they become solvated ­

  • don't conduct electricity in solid state,

  • but will when molten or in aqueous solution ­ brittle (crystals shatter under force)

Different Ionic Compounds have a different extent of Ionic Character

­ binary compound - contains 2 elements

  • Ionic Compound Electronegativity Difference- 1.8 or higher on the Pauling Scale

  • Pauling Scale Trend on PT- Increase along period , up a group

    Bonding Continuum

    Bonding Triangle

Covalent Bonding

  • 2+ non metals

  • form by atoms sharing electrons

  • shared electrons concentrated in region between 2 nuclei and is attracted to both

  • held together- electrostatic attraction (covalent bond)

  • formation of covalent bond - stabiizes atoms so energy is released as bond forms

  • forces of attraction between nuclei and shared electrons balanced by - forces of repusion between 2 nuclei (holds atoms apart at fixed distance)

  • octect rule- atoms react to acheive full valence shell with 8 outer electrons

  • diatomic molecules- 2 atoms

  • 3 atoms- triatomic

  • lone pair/non bonding pair- electrons not involved in forming bond, important in shape of molecule

    Atoms can share more than 1 pair of electrons to form multiple bonds

  • doube bond-

  • Short Bonds are Strong Bonds

  • bond length- measure between 2 bonded nucei

  • bond enthalpy- amount of energy needed to break bonds

  • multipe bonds- greater number of shared electrons

    • stronger electrostatic attraction between bonded nuclei