chapter 8.1 8.2 Flashcards
monoatomic
exist as a single atom (noble gases and helium)
covalent bonds
atoms held together by sharing electrons
molecule
a neutral group of atoms joined togeher by covalent bonds
diatomic molecule
molecule consisting of two atoms (oxygen molecule)
molecular compound
a compound composed of molecules
ex: water, carbon monoxide
melting and boiling points of molecular compounds
lower than ionic compounds
molecular formula
chemical formula of a molecular compound, shows how many atoms of each element a molecule contains
ionic vs covalent
ionic is metal and nonmetal, covalent is nonmetal to nonmetal
ionic is formula unit/lowest whole number ratio, molecular formula shows how many atoms of each element
why do covalent bonds have lower melting/boiling points
the covalent bonds are weaker
why dont covalent bonds conduct electricity in water
they don’t dissociate into ions
halogens form
single covalent bonds in their diamotic molecules
diatomics
io2, h2, n2, f2, cl2, br2, i2
unshared pair
a pair of valence electrons that is not shared between atoms
when do atoms form double or triple bonds?
when they can attain a noble gas stucture by sharing two pairs of three pairs of electrons
double covalent bond
two shared pairs
triple covalent bonds
three shared pairs
coordinate covalent bond
in which one atoms contrubutes both bonding electrons
polyatomic
tightly bound group of atoms with a positive or negative charge that behaves as a unit
resonance structure
structure that occurs when it is possible to draw two or more valid electron dot scturecutres that have the same number of electron pairs for a molecule or ion
the octet rule cannot be satisfied
in molecules who have an odd number of valence electrons
bond dissociation energy
the energy required to break the bond between two covalently bonded atoms
how to calculate eneryg of a reaction
energy of the reactants minus energies of the products
