1.3 Basics of Bonding Flashcards
what are covalent bonds a result of
constructively overlapping orbitals
what are the two main subdivided types of covalent bonds
sigma and pi bonds
what determines the type of covalent bond
how involve overlap the orbitals
whaat kind of overlap does sigma bonds have
they have head on overlap between two orbitals
what diffrent kinds of orbitals can be combined to produce sigma bonds? do they have to be the same kind? ie.. s and s, p and s?
a sigma bond may arise from any direct overlap between two properly aligned orbitals of the same phase
ie.. constructive bonds
what is constructive overlap
when the phase of the two orbitals being combined must be the same form of covalent bond
do sigma bond require s orbitals in there bonds
No. For example two properly aligned p orbitals may overlap and form a sigma bond
what is the only requirement of sigma bonding
the two portions overlapping combine constructively and in a direct overlap
what are pi bonds
they result from indirect (side-on) overlap between two orbitals
how do pi bonds compare to sigma bonds
unlike sigma bonds the two orbitals are not able to directly overlap and instead they come close together and slightly bend to constructive overlap
in a sigma bond + pi bond a drawing would represent 2 bonds when there is 3 lobes (areas of electron density) why is this
because the pi bond is made from overlap of both lobes on the p orbitals
in simple organic systems are pi bonds a result of
they are a result from a indirect overlap of two p orbitals
what is the geometric structure of a pi bond
there are two areas one above and one below the nuclei which form the bond
how many lobes are in a pi bond
two lobes make up one pi bond
what is electronagitivity
the relitive ability of an atom to attract electrons to itself in a chemical compound
is the electronegativity of an element a fixed property
no
what can electronegativity be influenced by
on its chemical environment because atoms are influenced by the neighbouring atoms in a chemical compound
what is the most common values for electronetitivity from
from the pauling scale
what is a polar bond
when two atoms with diffrent electronegitivities are covalently bonded together and an unequal sharing of electrons occurs
in a polar bond what atom takes the s- symbol
the atom that takes extra electron density (more elecronagitive atom)
in a polar bond what atom take the s+ symbol
the atom that gains less electron density (less electronegative)
what does the s- and s+ put emphasis on
that there are partial negative and positive charges on those atoms
are polar covalent bonds covalent or ionic
they can be thought of as being similar to ionic bonds but where the electrons are still shared between the atoms
what are the two ways to indicate if a bond is polar
- the s- and s+
-the large arrow pointing towards the more electronegative side
