4- Chemical Bonding and Structure

ionic bonding

the electrostatic attraction between two oppositely charged ions

cation

A positively charged ion

anion

A negatively charged ion

multivalent

describing the ability of an element to form ions in more than one way, depending on the chemical reaction it undergoes

votality

tendency to vaporize

covalent bonding

the electrostatic attraction between a positive nuclei and a shared pair of electrons

bond energy

energy required to break one mole of a covalent bond in gaseous molecules

delocalized electrons

electrons that are free to move in metals; they come from resonance bonding

resonance bonding

a double bond could appear in 2 (or more) locations

coordinate covalent bond

where a pair of shared electrons only come from one atom

bond order

the number of bonds between pairs of electrons

expanded octets

Occur for non metals in rows 4-7 where the central atoms can hold more than 8 electrons b/c the extra electrons expand/fill into the d-orbital

pure covalent bonds

bond that occurs between atoms that have no difference in electronegativity

polar covalent bonds

bond that occurs between atoms that have a different in electronegativity between 0.5-1.7 units

spectrum of bonding

a gradual shift from non-polar covalent bond to polar ones, and then to ionic

net dipole moment

a measure of its overall polarity, the sum of all the bond dipoles in a molecule

intramolecular bonds

bonds within molecules

intermolecular forces

forces of attraction between molecules

London dispersion forces

the intermolecular attraction resulting from the uneven distribution of electrons and the creation of temporary dipoles

instantaneous dipole

temporary dipole that occurs for a brief moment in time when the electrons of an atom or molecule are distributed asymmetrically

induced dipole

a dipole temporarily created in an otherwise nonpolar molecule, induced by a neighboring charge

Dipole-dipole forces

intermolecular forces that exist between polar molecules; the strengths this intermolecular attractions increase when polarity increases

Hydrogen bonding

strong type of intermolecular dipole-dipole attraction, occurs between hydrogen and F, O or N

giant covalent structure

covalent substances that don't exist as discrete molecules

allotropes

two or more different molecular forms of the same element in the same physical state

geodesic dome

a spherical structure formed by 20 hexagons and 12 pentagon shapes

alloy

a combination; a mixture of two or more metals/non-metals