molecular compounds
what are covalent bonds
share electrons and form molecules and compounds
how does the octet rule apply to covalent bonding
the combined atoms of covalent bonds usually acquire a total of 8 electrons by sharing electrons
sigma bonds
molecular orbitals that are symmetrical around the axis connecting 2 atomic nuclei
explain how carbon dioxide consists of 2 polar bonds yet is a nonpolar molecule
it has 2 polar bonds and is linear but the carbon and oxygen lie on the same axis so the polarity cancel out because they are in opposite directions
what are metal bonds
the forces of attraction between the free floating valence electrons and the positively charged metal ions
diatomic molecules
a molecule formed from 2 atoms
what are coordinate covalent bonds
when an atom donates both bonding electrons
pi orbitals
orbitals overlap side by side producing pi molecular orbitals which are then filled with 2 electrons
dipole interactions
occur when polar molecules are attracted to one another. the electrical attraction occurs between oppositely charged regions
2 elements that dont follow the octet rule
hydrogen and lythium
triatomic elements
a molecule formed from 3 of the same atom
what are polyatomic ions
created from oordinate covalent bonds, ions that make up of more than 1 atom
VSEPR theory stands for
valence shell electrons pair repulsion
dispersion forces
weakest of all molecular interactions, caused by the motion of electrons, occur even between nonpolar molecules
how can the number of valence electrons of an element be determined from its position in the periodic table
the atoms group on the periodic table determines the amount of valence electrons
review: ionic compound
composed of cations and anions
what does bond dissociation energy reveal about the strength of a covalent bond
reveals the energy required to break the bond between 2 covalently bonded atoms
how does VSEPR theory explain the difference in the molecular shape of methane and ammonia
methane has 4 bonding electron pairs and no unshared pairs, ammonia is surrounded by 4 pairs of valence electrons but one of the pairs is an unshared pair
hydrogen bonds
attractive forces where a hydrogen covalently bonded to a very electronegative atom is also weakly bonded to an unshared electron pair of another electronegative atom
convert 345K into celsius
345 - 273 = 72
whats the difference between ionic compounds and molecular compounds
an ionic compound is composed of cations and anions while a molecular compound is composed of molecules
what is a resonance structure
occur when indication is needed that 2 or more valid electron dot structures are possible
how are hybrid orbitals formed
when several atomic orbitals mix together
why do network solids have much higher melting points than other covalent compounds
Due to the strength of the covalent bonds, covalent network solids have high melting points
what are the shapes of s orbitals p orbitals and d orbitals
s - spherical
p - dumbbell
d - clover leaf