Unit 2 Flashcards
ionic bond
transfer of electrons between metal and nonmetal. greater than 1.7 electronegativity between the atoms
brittle
covalent
sharing of electrons between two nonmetals can be polar and nonpolar
polar
unequal sharing of electrons (when it has a charge) 0.5-1.7
nonpolar
equal sharing of electrons (symmetric) <0.5
metallic bond
between metal atoms; attraction due to multiple metallic cations being attracted to a delocalized sea of valence electrons
can be pure, interstitial, and substitutional
metal properties
good conductors of heat and electricity
malleable
ductile
lustrous
-> metal atoms lose electrons to form cations
properties of covalent
- brittle
- poor conductors
- form anions by gaining electrons
cations
positively-charged ions
anions
negatively charged ions
bond enthalpy
energy required to break a bond/ energy released when bond is formed.
-> greater radius = longer bond length
-> longer bond length = decrease in bond energy
lattice energy
energy to separate ions in ionic compounds
-> larger charges = higher lattice energy
-> smaller raddii = higher lattice energy
ionic solids characteristics
- high melting points and
- nonvolatile (reactive)
sea of electrons
electrons move around and dont stay in one place
ionic radius decrease attraction increase
alloys
mixtures of metals
interstitial
substitutional
interstitial alloys
atoms added to metal are small and fit INBETWEEN metal atoms
substitutional alloys
atoms added have similar radii as metal, replace atoms in the lattice
LEWIS DIAGRAM BUILDING
- count # of electrons
- subtract # of electrons that were used for pairing
- add remaining electrons as dots
- look to add multiple bonds if not all atoms acheived octets
- add remaining to central atom
- add [] if it is an ion + the charge
- look for formal charge so we have the best version of the lewis diagram (all must be 0 or have the charge on the most electronegative atom)
formal charge
determines which lewis structure is most valid
-> count bonds as one electron
VALID STRUCTURES
- formal charge as close to 0 for all atoms
- negative formal charge will be placed on most electroneg atom
resonance structures
draw arrows between all models that signify the same thing
bond lengths are avg of bonds present ex : -1 = -1/2 and -1/2 on both of the side atoms (no brackets needed)
VSPR theory
valence shell electron pair repulsion
X–M–X
sp
X–M-X-X
spp
bond polarity
difference in electronegativity values of two elements
properties of metals :
- lustrous
- Malleable
- Ductile
- good conductors of heat and electricity
– metal atoms lose electroms to form cations
nonvolatile
not reactive
