6.2 : Electronegativity and Polarity Flashcards
What can cause electronegativity ?
The nuclear charges are different
The atoms may be different sizes
The shared pair of electrons may be closer to one nucleus than the other
Define electronegativity
The attraction of a bonded atom for the pair of electrons in a covalent bond
How is electronegativity measured?
Paulings Scale
Describe the trend in electronegativity across the periodic table
The higher the atom is and the more towards the right the atom is :
The nuclear charge increases
The atomic radius decreases
Describe electronegativity of specific groups
Noble gases not included as the don’t tend to form compounds
Non metals : nitrogen, oxygen, fluorine and chlorine have the most electronegative atoms
Group 1 metals ( lithium, sodium, potassium ) have the least electronegative atoms
How can you tell what type of bond it is depending on the difference in electronegativity ?
0 = covalent
0-1.8 = polar covalent
1.8 + = ionic
When will a bond be non polar?
The bonded atoms are the same
They have the same or similar electronegativity
This is a pure covalent bond
Define dipole
Separation of opposite charges
How does symmetry affect polarity?
Symmetrical = dipoles cancel = non polar
