The Ammonium Cation Lecture | Lecture Note

University:
Purdue University
Course:
CHM 62100 | Advanced Analytical Chemistry
Academic year:

2019
Views:

313

Pages:

10
Author:

rezancuk2j

The ammonium cation The hydronium ion Polarity • In chemistry substances can be considered polar or non-polar. • Polar- Molecules and ionic substances( formula units) can be considered Polar as they have positive and negative charge). • A polar molecule( Polar covalent substances) arises when one of the atoms exerts a stronger attractive force on the electrons in the bond. The electrons get drawn more towards that atom, so that the molecule exhibits a slight charge imbalance. It is worthy to mention that all ionic substances are polar because formula units have cations( +) and anions(-). Non- Polar- ( No opposite charge difference).A non polar molecule consists of atoms with the same electronegativity so that there is not much charge imbalance or very little difference in charge. Important: When dissolving substances it is worthy to mention the all time favorite idea that: Like dissolves Like This means that you need a polar substance to dissolve a polar substance and you need a non-polar substance to dissolve a non-polar substance. Electronegativity can be calculated from Pauling scale of electronegativity values Non-Polar covalent molecules Polar covalent molecules Other examples of polar covalent molecules include •HF , HCl and NH3 (ammonia) Please know though that majority of covalent substances are nonpolar