Bonding Flashcards
cation
positively charged ion
anion
negatively charged ion
dative bond
a covalent bond where both electrons in the shared pair are donated from the same atom
Covalent bond
the electrostatic attraction between nuclei of two non metal atoms and the bonding electrons of their outer shells. no electrons are transferred, they are only shared
shorter bond length means
greater bond strength as bonding pair is closer to atoms nucleus
as number of shared electrons increases, bond length
decreases
linear bond angle
180
trigonal planar bond angle
120
tetrahedral bond angle
109.5
trigonal bipyramidal bond angle
90 and 120
octahedral bond angle
90
how many degrees is subtracted when a bond pair is replaced with a lone pair eg: trigonal planar to bent
-2
valence shell electron pair repulsion theory
All pairs of valence electrons will repel each other to the maximum separation that they can where they experience the minimum amount of repulsion.
pyramidal bond angle
107
bent bond angle
118 or 104.5
do bond pairs or lone pairs repel more
lone pairs
electronegativity
Measures the attraction of a bonded atom for the pair of electrons in a covalent bond
3 most electronegative elements
Fluorine, oxygen and nitrogen
dipole
an area of slight positive or negative charge
what leads to a polar covalent bond
electronegativity difference
where does an electron lie in a polar covalent bond and what does this cause
closer to the more electronegative atom, giving the more electronegative atom a slight negative charge and the less electronegative atom a slight positive charge
polar molecule
a molecule which can be split into 2 overall dipoles
can symmetrical molecules be polar, why
no because the dipoles for each end cancel out
dipole-dipole interactions
both molecules have permanent dipoles which cause them to attract eachother
dipole-induced dipole interactions
permanent dipole induces a dipole on another molecule which causes them to attract
london forces
instantaneous dipoles form due to electron movement causing momentary attraction
what happens to london forces as the size of a molecule increases, why
the strength of london forces increases as there are more electrons to form a stronger instantaneous dipole
order of intermolecular forces in increasing strength
london forces —–> dipole-dipole —–> hydrogen bonds
where does hydrogen bonding occur
between molecules that have a F, O or N that has a lone pair of electrons and is also covalentally bonded to a H atom
what is a hydrogen bond
an extra strong dipole-dipole interaction
why is water denser than ice
hydrogen bonds in water holds molecules closer together than the lattice it forms when frozen
