ionic and covalent bonding

Ionic and Covalent bonding

David A. KatzPima Community College

Tucson, AZ

Ionic Bonding

Between a metal with low ionization energy( little energy required to remove an electron)

and a non-metal with high electronegativity and electron affinity

( wants to grab an electron towards it)

Formation of NaCl

Lewis Structures for Ionic Compounds

Ba•• O•

•••

••

••O••

••

••Ba2+ 2-

Mg••

Cl•••

••

••Cl•••

••••

••Cl••

••

••Mg2+ -

2

BaO

MgCl2

Held together by strong electrostatic forces• Opposite charges attract• High melting points and boiling points• Regular structures – giant ionic lattices• When melted or dissolved ionic compounds conduct electricity

Properties of Ionic Compounds

Dissolving in Water

conductivity

Covalent Bond

• Between two elements with high ionization energy ( do not give up electrons easily) and high electronegativity ( try to grab the electron to each of them)

• Here neither atom is willing to give up its electron

• Instead the nuclei share the electrons between them

Lewis Structures

• Lewis structures are representations of molecules showing all electrons, bonding and non-bonding

Example :Li2 O

Lewis structures

F2 C2H6

Multiple Covalent bonds

• More than one pair of electrons can be shared between the same atoms

O2 N2

Properties of Covalent Molecules

• Contain non-metals• Weak bonds• Valence electrons are shared between atoms• Polar molecules dissolve in polar solvents• Volatile• Low melting and boiling points• Insoluble in water• Non polar compounds do not conduct

electricity; polar compounds can conduct small amounts of electricity