Lecture 8 Flashcards
metals
fewer valence electrons, resulting in lower IE, therefore a lower electronegativity
non-metals
more valence electrons, resulting in higher IE, therefore a higher electronegativity
ionic bonding
full transfer of electrons from a metal to a non-metal
covalent bonding
equal sharing of 2 valence electrons in a bonding orbital between atoms of similar electronegativities, therefore no polarization
polar covalent bonding
- uneven sharing of 2 valence electrons in a bonding orbitals due to difference in electronegativies
- stronger because of the opposite charges
metallic bonding
- valence electrons delocalized over many atoms via their valence orbitals (bonds of orbital)
- delocalization of electrons leads to conductivity, thermal conductivity, or ductility
covalent bond strength
- depends on overlap between the bonding atomic valence orbitals
- orbitals must point towards each other
- same size orbitals cause better overlap
ionic bond strength
- small, medium sized orbitals cause good overlaps
- one large and one small orbital causes poor overlap
- both large orbitals causes decent overlap
Valence Shell Electron Pair Repulsion (VSEPR)
bonding pairs and lone pairs repel and molecules will adopt geometries that minimize repulsions by maximizing space
AX2
- linear
- 180°
AX3
- trigonal planar
- 120 °
AX4
- tetrahedral
- 109.5°
AX5
- square pyramidal
- trigonal bipyrimidal
AX6
- octahedral shape
- 90°