3.1.3.6 Bond polarity Flashcards
Definition: electronegativity
tendency / strength / ability / power of an atom / element / nucleus to attract / pull / withdraw electrons / e - density / bonding pair / shared pair
in a covalent bond
why the O–H bond in a methanol molecule is polar
Oxygen more/very/highly electronegative (than hydrogen) OR oxygen has stronger attraction for bonding electrons / bonding electrons drawn towards oxygen;
causes higher e– density round oxygen atom / causes Hδ+
Oδ–
Definition: electronegativity
The power of an atom or nucleus to withdraw or attract electrons or electron density or a pair of electrons (towards itself)
in a covalent bond
Ethanedioic acid is a weak acid. Ethanedioic acid acts, initially, as a monoprotic acid.
why the acid strengths of ethanedioic acid and ethanoic acid are different
Stage 1: difference in structure of the two acids
• The acids are of the form RCOOH
• but in ethanoic acid R = CH3 • whilst in ethanedioic acid R = COOH
Stage 2: the inductive effect
• The unionised COOH group contains two very electronegative oxygen atoms
• therefore has a negative inductive (electron withdrawing)effect
• The CH3 group has a positive inductive (electron pushing) effect
Stage 3: how the polarity of OH affects acid strength
• The O–H bond in the ethanedioic acid is more polarised / H becomes more δ+
• More dissociation into H+ ions
• Ethanedioic acid is stronger than ethanoic acid
Definition: electronegativity
Ability/power of an atom/element/nucleus to withdraw electron density or electron cloud or a pair of electrons (towards itself);
From a covalent bond or from a shared pair of electrons;
the meaning of the symbol δ+
in a bond between nitrogen and hydrogen can be represented
small, slight, partial positive charge
Electron deficient
what can be deduced about the electronegativity of hydrogen relative to that of nitrogen
H < N
why the O–H bond in a methanol molecule is polar
Oxygen more/very/highly electronegative (than hydrogen) OR oxygen has stronger attraction for bonding electrons / bonding electrons drawn towards oxygen
causes higher e– density round oxygen atom / causes Hδ+ Oδ–
property of the atoms involved causes a bond to be polar
Electronegativity (difference) or suitable description
Definition: electronegativity
The power of an atom or nucleus to withdraw or attract electrons OR electron density OR a pair of electrons (towards itself)
In a covalent bond
why the electronegativity of the elements increases from lithium to fluorine
More protons / bigger nuclear charge
Same or similar shielding / electrons in the same shell or principal energy level / atoms get smaller
Definition: electronegativity
The power of an atom or nucleus to withdraw or attract electrons or electron density or a pair of electrons (towards itself)
in a covalent bond
Definition: electronegativity
Ability/power of an atom/element/nucleus to withdraw electron density or electron cloud or a pair of electrons (towards itself)
From a covalent bond or from a shared pair of electrons
which property of the atoms involved causes a bond to be polar
Electronegativity (difference)
Definition: electronegativity
Power (or ability) of an element / atom to attract electron pair/electrons/ an electron/electron density
In a covalent bond
