Atoms form theri bonds through
valence electrons
ionic bond
Bonding if metal atoms which have low ionization energy with a nonmetal atoms that have high electron affinity
Energy of the crystal lattice
representing the released potential energy in creation of an ionic compound
lattice energy is the quantity of energy released during the formation of
one mole of single crystal
E of lattice depends on the radius
radius smaller -> E of lattice bigger
E of lattice depends on the charge of the ion
charge bigger -> E of lattice bigger
bond between ions is of
electrical nature
all ionic compounds are of
crystalline nature
all ionic compounds have a
high melting pont
high boiling point
all ionic compounds are
soluble in water
In Ionic crystals
each cation is surrounded by a number of anions and vice versa
In Ionic crystals the molecules are gathered by
attractive force which is stronger with higher charge and smaller ion
lattice structure depends on
the size of cations and anions, their charges and their stoichiometry
covalent network crystals
atoms at lattice points
covalently bonded
hard
high melting and boiling point
do not conduct electricity
Molecular crystals
structural units are molecules
can sublimate
have lower boiling and melting points than ionic crystals
Molecular crystals are gathered by
weak attractive van der waals forces
Covalent bonds
valence orbitals of two atoms with one electron of opposite spin overlap
the strength of Covalent bonds depends on
the bond type and the amount of overlapping
Sigma Covalent bonds
primary
maximum electron density between the nuclei
symetric
pi Covalent bonds
symetry of a molecule depends on
repulsing of orbitals with shared elecreons and orbitals with undivided electron pair
is the repulsion of an ion pair or a bonding pair greater?
Ion pair
properties of covalent compounds
electronegativity
the tendency of an atom or a functional group to attract electrons (electron density) towards itself
what is the most important molecular dipole
Water
concequences of molecular dipole are attractive forces between them called
intermolecular attractive forces
(Van der Waals!!!)
London attractive forces occur in conditions of
high pressure and low temperature -> may become dipoles
Hydrogen bonding
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