U1-3-1 - Bond Polarity Flashcards
Part of the Structure and Bonding topic from Unit 1 of Higher Chemistry, Chemical Changes and Structure
Formula for phosphorus
P4
Formula for sulfur
S8
Name all covalent network elements
Boron, silicon, carbon
Pure covalent bond
A bond in which bonding electrons are shared equally.
Also called ‘non-polar bond’
Polar bond
A bond in which bonding electrons are shared unequally and which has a permanent dipole.
What causes chemical bonds to be polar?
Electronegativity difference between bonding atoms.
(usually ≥0.4)
How do you determine the ‘ionic character’ of a bond?
Calculate electronegativity difference.
Higher ΔEN = more ionic character (bonding e- shared less evenly)
What do δ+ and δ− mean?
Delta plus/delta minus - partial charges
A compound has a low melting/boiling point and does not conduct electricity in any form.
What bonding and structure does it have?
Covalent molecular
A compound has a very high melting/boiling point and does not conduct electricity in any form.
What bonding and structure does it have?
Covalent network
A compound has a very high melting/boiling point and conducts electricity when molten/dissolved.
What bonding and structure does it have?
Ionic (lattice)
Li+2S2−
What is wrong with this ionic formula?
More than one of Li+ present, must be shown in brackets:
(Li+)2S2−
