Exam 1 Flashcards
What is the limit on the number of valence electrons the second row of elements can have?
8
formal charge main formula and condensed
Main: Formal charge=(#of starting valence electrons)-((lone pair e)+(1/2 bonding e))
or
valence electrons-(Dots+lines)
covalent bond
Electrons are shared equally between two atoms. Aka nonpolar bond, electronegativity difference is between 0 and 0.4
Polar covalent bond
electrons are shared between atoms but not equally, resulting in induction. Electronegativity difference is between 0.4 and 2
induction
withdrawal of electrons toward an atom, resulting in partial negative and positive charges
Ionic bond
Electrons are not shared, but form a bond due to the force of attraction between opposite charges. Electronegativity difference is between 2 and 4. No electron charge, purely electrostatic.
Which atom is an exception to the octet rule and why?
H because it doesn’t have enough electron orbitals
What happens when atoms obey the octet rule?
atoms are stabliized at a lower energy level
What formal charge do neutral atoms have?
0
what does a formal charge tell you?
how far the charge is from the correct number of valence electrons
what does electronegativity indicate?
how strongly atoms pull electrons towards themselves
Vectors
Arrows in lewis diagrams pointing the more electronegative and more electron dense atoms. Length of vector indicates magnitude
dipole moment
quantification of the induction that occurs in polar covalent bonds
molecular bond polarity
the vector sum(or middle of the vectors) of a molecule with more than 2 atoms. This describes what the entire molecule is doing
intermolecular forces vs intramolecular forces
inter: BETWEEN molecules, not true bonds and weaker than true bonds
intra: with the same molecule
intermolecular forces from strongest to weakest
H bonding, dipole-dipole then dispersion forces
how to tell strength of dispersion forces
more surface area(#of C atoms) means stronger dispersion forces because charges are farther away from each other
How does branching effect surface area?
branching decreases it
atomic orbitals
describe where electrons exist within an atom based on wave equations that take into account the wave like nature of electrons, refers to space with 90-95% electron density
what happens with orbitals in bonds between atoms?
orbitals must overlap so electrons can be shared
S orbital
spherical in shape, almost all atoms have them
P orbitals
“dumbell” or infinity sign shaped
Aufbau principle
fill lowest energy orbital first
Pauli
each orbital accomodates max of 2 electrons with opposite spin