Chemical Bonding Flashcards
What is an orbital?
Region of space around an atoms nucleus where an electron may exist
It’s a 3D space that defines where an electron may be
What are the four rules of Bonding Theory?
The first energy level has room for only one orbital = 2 electron math
Energy levels above the first have room for four orbitals = 8 electrons max
An orbital can be unoccupied or it may contain one or two electrons - but never more then two
Electrons spread out to occupy any empty valence orbitals before forming electron pairs
What are Lewis Symbols?
Named after Gilbert Lewis who is responsible for the Octet Rule. He reasoned that all atoms strive to be like the nearest noble gas
Used dots or x to represent the valence electrons
The inner electrons and the nucleus are represent by the element symbol
What is electronegativity?
A measure of the force that an atom exerts on electrons of other atoms
The greater number the greater the force
How do we assign each atom an electronegativity?
The greater number of protons in the nucleus, the greater the attraction for more electrons
What is covalent bonding?
Both atoms have a high EN so neither atom “wins”
The EN difference can be zero or small
What is ionic bonding?
The electronegativity of the two atoms are quite different
The atom with the higher EN will remove the bonding electron from the other atom (electron transfer occurs)
Positive and negative ions are formed which attract each other
What is metallic bonding?
Both atoms have a relatively low EN so atoms share valence electrons, but no actual chemical reaction takes place
Electrons are not held very strongly by their atoms
The atoms have vacant valence orbitals
What is VSEPR?
Valence Shell Electron Pair Repulsion
Pairs of electrons remain as far apart as possible due to the repulsive forces of their negative energy
What is the VSEPR shape linear?
Two bonds and no lone pairs on the central atom
Bond angle: 180
General form: AX2
What is the VSEPR shape trigonal planar?
Three bonds and no lone pairs on the central atom
Bond angle: 120
General form: AX3
What is the VSEPR shape tetrahedral?
Four bond and no lone pairs on the central atom
Bond angle: 109.5
General form: AX4
What is the VSEPR shape trigonal pyramidal?
Three bonds and one lone pair on the central atom
Bond angle: 107.3
General form: AX3E
What is the VSEPR shape angular?
Two bonds and two lone pairs on the central atom
Bond angle: 105
General form: AX2E2
What is the VSEPR shape linear (tetrahedral)?
Two bonds and three lone pairs on the central atom
Bond angle: 109.5
General form: AXE3