inorganic 3- shapes and isomers Flashcards
Why does a chemical bond form
if the bond (resulting arrangement of the nuclei and their electrons) has lower energy than the total energy of the separate atoms
Define covalent bond
pair of electrons shared between 2 atoms
what is the goal of a covalent bond
to get as close to being an octet by sharing electron pairs
a lewis structure shows — electrons
valence electrons
What is an element with an unpaired electron considered
a radical
How would a lewis structure represent this
What is a 2c-2e bond
2 centre 2 electrons
calculate the number of valence electrons of [BF4]-
what does hyper valence mean
molecule that has an element containing more than 8 valence electrons
is a dative bond any different energetically from a normal covalent bond
no
what is a dative bond
One atom donating a lone pair of electrons in one orbital into a vacant orbital on another atom = dative bond
what hybridisation is nitrogen in ammonia
sp3
How many valence electrons, and therefore pairs of electrons in SO4 2-
equation for formal charge
How do you get to the electrons being hybridised
excite 2s electrons to 2p level
Why can elements get a higher co-ordination number as you go down the group
radius of the elements gets bigger
How would these sulphur electrons hybridise/arrange to form SF6
most energetically stable way to arrange 6 F bonds/ all S-F bonds must be the same energy
how is molecule shape dictated and what assumptions do we make to decide it
electron repulsions. assumption= all bonds are covalent
What type of elements do we not use VSEPR theory to predict molecule shape for
VSEPR applicable to s- and p-block compounds. d-block compounds (complexes) have shapes dictated by the number of ligands
What is the heirachy of electron repulsion
If all sites are equal (octahedral geometry) then where will the lone pairs be paired in relation to one another
lone pairs will be trans (opposite)(180° angle)
Bonding pairs to electro—- substituents occupy less space than those to more electro— substituents.
Bonding pairs to electronegative substituents occupy less space than those to more electropositive substituents.
Where would a lone pair go on this arrangement
will always be equatorial in a trigonal bipyramidal
When deciding a molecule shape, do double bonds or single bonds take up more space
double bonds take up more space