Chem Test 2

hasanahatesenglish's version from 2017-10-16 02:24

Section 1

Question Answer
valence bond theoryquantum mechanically based theory explaining covanlent bond formation/molecular shape based on ORBITAL OVERLAP. based on principle that these bonds form when atomic orbitals of 2 atoms overlap to share region in space and when a pair of electrions occupy the region where it overlaps
molecular orbital theoryproposes when atomic orbitals overlap they combine n form new orbitals called molecular orbitals. have new shapes n energy levels and electrons are dissociated from the new orbital
hybrid orbitalsorbital that is formed by the combination of 2 or more orbitals in a valence shell of an atom
Sigma bond overlapbond/overlap that is symmetrical around bond axis of 2 nuclei. rotation doesnt change the orienation. created by end to end overlap of atomic orbitals (s-s, s-p, p-p)
Pi bond/overlapsideways overlap of p orbitals. present in double and triple bond. 2 lobes of each p orbital overlap creating 2 areas of overlap on either side of bond axis. rotation around bond axis is not pssoible without breaking the PI overlaps
single bond1 sigma
double bond1 sigma 1 pie
triple bond1 sigma 2 pie

Section 2

Question Answer
valance bond theory- The Region of orbital overlap has a maximum capacityof 2 electrons and the electrons should have oppisite spins according to pauli exclusion principle
There should be a maximum overlap of orbitals. the greater the orbital overlapthe stronger and more stable the bond is. orbital overlap depends on shape and direction of the orbital that are involved in bonding
to help explain the observed molecular shape of some moleculethe concept of atomic orbital hybridization is used. this is the combing or mixing of atomic orbitals to produce new atomic orbitals

Section 3

Question Answer
VSPER theory (valance shell electron pair repulsion theory)all pairs of electrons repel each other and get as far from each other as possible
valance electrons of central atom are importantas it determines shape of molecule
valance electrions are paired or will be pairedin a molecule
bonded pair of electronsand lone pairs are treated equally
valance electron pairs will repeleach other
molecular shape is determined byposition of electron pairs when they are positioned max distance apart in order to minimize repulsion

Section 4

Question Answer
factors that determine shape of a molecule include bond lengths and bond anglesa bond angle is the angle formed between the nuclei of 2 atoms that surround the central atom of the molecule