chem chemical bonds Flashcards
chemical bonds
atoms come together in small or large bonds forming stable associations
-metallic
-covalent
-ionic
why do chemical bonds occur§?
as a result of changes in the distribution of e
ionic bonds
-ions are in a lattice structure
-more flexible when elements come from diff ends
positive ions
cations
lose e
negative ions
anions
gain e
ending in -ide
nuclear charge
=atomic numb
ionic exceptions
Fe 2 3
Pb 2 4
Sn 2 4
Ag 1
Cu 1 2
what is the effective n c and the n c of Li?
+1 and 3
diagram for formation of cations and anions
the circles that represent the energy levels with electron pairs
equation for formation of cations and anions
Al = Al3+ + 3e cation anion
N+ 3e = N3-
ionic bonding
instead of ionic bond
-one atom donates e one accepts
NaClO
ionic
in which cases is it harder to add e?
increasing neg charge due to increased e e repulsion
ultimate goal
stable electron conf
metals- noble gas proceeding
non metals- noble gas succeeding
polyatomic ions
NO3-
SO4 2-
PO4 3-
OH-
HCO3 -
CO3 2-
NH4 +
lattice structure
-neutral charge
-electrostatic force
fixed arrangement
lattice enthalpy
energy needed to break an ionic bond, separate ions, it is endothermic so positive NaCl Na Cl
-bigger ions smaller enthalpy
-bigger ion charge bigger enthapy
prop-high melting and boiling points
-because a lot of E in necessary to separate the ions in the lattice
-higher when ionic charge is greater (like lattice enthalpy)
prop-volatility
non volatile because of strong electrostatic attractions
prop-solubility
-in water
-not in non polar
-the attraction of the surface crystal ions t the water molecule pulls the ions away from lattice positions
hydration energy
energy given out when the ions become hydrated
prop-conductivity
-high electrical conductivity
-only in aq or l states
-only when molten because then the ions are free to move and therefore conduct
prop-brittle
it breaks with force
% ionic character
electronegativity diff : 3.2
-zero= non polar covalent
-zero to 1.8= polar covalent
-1.8 < = ionic
Delta xp
electroneg. diff, CsF is 3.2, 100% ioc
actual tests to determine ionic comp
-melting point
-conductivity
-solubility
to oxidize
it means to cause a reaction in which e are lost to another species
covalent bond
electrostatic attraction between a shared pair of e and the nuclei of the atoms making up the bond
formation of covalent bond
-draw=two circles connected with shared electrons
-when two non metals react they are seeking to gain e to achieve a stable e conf of a noble gas, so they share electrons
