Structure 2.2: The Covalent model Flashcards
What is a covalent bond?
Electrostatic attraction between a shared pair of electrons and positively charged nuclei
Main difference between covalent and ionic bonding
Ionic - metal and non metal
Covalent - between non metals
What is bond strength?
Energy required to break a bond
What is bond length?
Measure of distance between 2 bonded nuclei
What is electronegativity?
Tendency of an atom to attract a bonding pair of electrons in a covalent bond
EN value for non-polar covalent molecules
Between 0-0.4
EN value for polar covalent molecules
Between 0.4-1.8
What is a polar covalent molecule?
A molecule with permanent dipoles (due to diff. in EN) and an asymmetrical geometry of P.C. bonds, and so dipoles cancel each other out (H2O)
What is a non-polar covalent molecule?
A molecule with permanent dipoles and a symmetrical geometry of P.C. bonds, and so dipoles cancel each other out (CO2)
How does the number of protons affect electronegativity?
More the protons, stronger the attraction
How does atomic radii affect electronegativity?
Smaller the atomic radii, stronger the attraction
How does shielding affect electronegativity?
More shielding, weaker the attraction
Why does electronegativity decrease down a group?
Due to an increase in atomic radii and shielding, electrostatic attraction on the electron pair decreases
Why does electronegativity increase across a period?
Due to a decrease in atomic radii and an increase in protons, electrostatic attraction on the electron pair increases
What is MG and BA in 2 BP and 0 LP
Linear, 180
