Chapter 8 Flashcards
How is a ionic bond structured?
Packed together
Ionic Bond
The electrostatic force that holds the ions together in an ionic compound`
Lattice Energy
The energy required to separate 1 mol of a solid ionic crystalline compound into its gaseous ions
Trends in Lattice Energy
Ions with a greater charge create higher lattice energy
Smaller ions get closer together, increasing lattice energy
Melting points increase with lattice energy
Covalent Bond
A bond in which two electrons are shared by two atoms
What electrons does covalent bonding use?
Valence electrons
Lewis Structure
A representation of covalent bonding in
which shared electron pairs are shown either as lines or as pairs of dots between two atoms, and lone pairs are shown as pairs of dots on individual atoms
Multiple Bonds
Bonds formed when two atoms share two or more pairs of electrons
Corollary
Energy is released when a bond is formed
Bond Dissociation Energy
Amount of energy required to break a mole of bonds of a certain type
It is an average value calculated from a number of different compounds containing the same bond
Higher bond dissociation energy = stronger chemical bond
Polar Bonds
When electrons spend more time near one nucleus than the other
How do we determine if a bond is covalent or ionic?
Electronegativity of the bonding atoms, if the difference is equal to or greater than 1.7 then the bond is ionic
How to make a Lewis Structure?
- Write the skeletal structure of the molecule
- Count the total number of valence electrons in the structure
- Draw a single covalent bond between the central atom and all surrounding atoms
- Complete octets
- If the centra atom has fewer than a full octet, make double or triple bonds
Formal Charge
The electrical charge difference between the valence electrons in an isolated atom and the number of electrons assigned to that atom in a Lewis structure
Resonance
The use of two or more Lewis Structures to represent a particular molecule
