orbital theory, electron. configurations and hybridisation Flashcards
define quanta
fixed amounts of energy
define wavefunction
both a wave and a particle
define ellipsoids
a dumbell shape
define orthogonal
right angled
define valency
the number of bonds needed to complete the shell
define orbital hybridisation
mixing up atomic orbitals to give new molecular orbitals
define sigma bonds
the strongest type of covalent chemical bond, which is formed when atomic orbitals overlap in a head-on arrangement to form a single bond
define pi bond
covalent bonds formed from the overlap of two orbital lobes on one atom twice side by side to form a double bond. the electron density lies in the pi bond, and can form with an existing pi bond to form a triple bond
define lone pair
paired electrons occupying one or more of the hybridised orbitals
what model is the atom described with?
the solar system model
what are the features of the solar system model?
a small, positively charged nucleus with electrons orbiting around it
what do the lines in the hydrogen emission spectrum come from?
the electron transitions in the atom which require quanta to move between
how do electrons jump between orbits?
by either absorbing or emitting electromagnetic radiation
what equation can we use to describe the change in energy between shells?
ΔE = hv
what are the four types of atomic orbital?
s, p, d, f
describe an s orbital
spherical, centred on the nucleus and has the highest probability of being the closest to the nucleus
describe a p orbital
two ellipsoids with a point of tangency at the nucleus, which are orthogonal to each other along the x, y, and z axis
describe a d orbital
has four pear-shaped lobes, all in one plane
how can we achieve orbital hybridisation?
we need to promote electrons within the atomic orbital shells, which requires energy input
what are the three hybridisations of shells?
SP, SP2, SP3
describe SP3 hybridisation
- combines the s orbital and all three p orbitals
- tetrahedral shape
- 109 degree bond angle
- all bonds are sigma bonds
describe SP2 hybridisation
- combines the s orbital and two of the p orbitals
- trigonal planar shape
- 120 degree bond angle
- carbon-hydrogen bonds are sigma, but the carbon-carbon bonds are a pi bond
describe SP hybridisation
- combines the s orbital and one p orbital
- linear shape
- 180 degree bond angle
- carbon-hydrogen bonds are sigma, but carbon-carbon bonds are a triple bond
why do lone pairs compress the bond angles?
they are held close to the atom than bonding electrons, and thus exert more repulsion
