Ions
• Ion – Charged Atom
• Cation - positive charged atom
• Anion negative charged atom
• Charge equals the A group number
Poly atomic Ion - Charged particle formed by a group of covalently bonded atoms.
Formulas
• Molecular Formula – exact number and type of atoms present
• Empirical Formula – Simplest whole number ratio of atoms present in a molecule or compound.
Valence Electrons
• The number of electrons in the outer level of an atom. Equals the A group number
....Se Mg. .. .Na . ...
Cl: .. ..
..Na . ...
Cl: ..+ Na+ -...Cl: ..
..
Ionic Bond
bond formed by the giving or
taking of electrons
Al3+
+ O2- Al2O3
Mg2+
Cl MgCl2+
Na+
N3+
NaN3+
Properties of Ionic Compounds
Formed from a metal and a non metal
Most are soluble in water
Form crystalline lattices
Covalent Bond
bond formed by the Sharing
of electrons
Br..: ...Br.. :...
+ Br..: ...Br.. :...
bonding pair
nonbonding pairs
Properties of Covalent Compounds
Formed by two nonmetals
Solubility varies
The strongest bond
Polarity
Slight charge differences in a molecule due to atoms having different
electronegativity
Electronegativity
The attraction an atom has for a pair of shared electrons
More Electronegative
Polar Covalent Bond
• Bond formed with unequal sharing of electrons
-Br..: ...
Br..: ...H. H.
+
Ionic bond
Covalent bondPolar Covalent bond
Bond lengths
The distance between the nuclei of two covalently bonded atom.