Chemical Bonding Flashcards
A chemical bond is formed due to following two reasons
To lower down the potential energy, and to increase stability
To attain noble gas configuration by completing its octet.
Ionic bond is also known as
electrovalent Bond and non-directional bond.
Atom which is having less, electronegativity should have
low ionization energy
The atom, which is having high electronegativity should have
high electron affinity.
The alkali metals and alkaline earth metals, one combined with nonmetals form,
ionic bonds.
LiCl is having more …….. nature.
covalent
Hence, it is more soluble in pyridine and acetone
BeCl2 is also having
covalent bond.
AlCl3 is covalent and forms,
dimer are to Al2Cl6,
But in aqueous solution due to high hydration enthalpy of Al3+ and Cl- it becomes ionic in nature.
Define lattice energy.
It is the energy required to break one mole of ionic solid into its gaseous ions.
Define enthalpy of formation.
It is the energy required or released when one mole of the compound is formed from standard state of its element.
Standard state of different elements
Hydrogen is gas
Fluorine is gas
Chlorine is gas
Oxygen is gas
Sodium is solid.
Magnesium is solid
Potassium is solid
Iodine is solid
Carbon is solid
Bromine is liquid
Mercury is liquid
Calculation of lattice enthalpy is done by
Born Haber Cycle
Lattice enthalpy is proportional to
Q+Q- / r+r-
Q + is the charge of cation.
Q- is the charge of anion.
r+ is the radius of cation.
r- is the radius of anion.
Hydration enthalpy.
It is the energy released. When one mole of the compound is dissolved in excess of water.
In case of any other solvent, it is known as solvation enthalpy.
It will be always exothermic.
Hydration energy is proportional to
Q+*Q-
1/r+ * 1/r-