However, the bonding electrons in the sulphur are further from the nucleus, and so the attraction is lessened. So sulphur is less electronegative than oxygen. Calcium is higher in the group than barium, so will have a higher electronegativity.

fluorine

Oxygen is more electronegative than chlorine because of the following reasons : Oxygen is placed towards the left side of fluorine so has one electron less than fluorine. Chlorine is below fluorine and has a new shell of valence electrons is added to it.

Sulfur is more electronegative than calcium.

Electronegativity. Sulfur is less electronegative than oxygen (2.4 and 3.5, respectively) and as a consequence bonds to sulfur are less polar than the corresponding bonds to oxygen.

Hydrogen has an electronegativity of 2.20 and sulfur has an electronegativity of 2.58. The electronegativity difference is 0.38.

Sulfur atoms have been known to participate in hydrogen bonds (H-bonds) and these sulfur-containing H-bonds (SCHBs) are suggested to play important roles in certain biological processes. It is revealed that sulfur atom is a very poor H-bond acceptor, but a moderately good H-bond donor.

Electronegativity is the tendency of an atom to attract shared pair of electrons towards itself. Electronegativity increases from left to right in a period while it decreases down the group. Hence, Carbon is more electronegative than Sulphur because C lies in second period while Sulphur lies in third period.

On the Pauling scale the electronegativity of nitrogen and oxygen are respectively 3.0 and 3.5. Oxygen has 8 protons in the nucleus while nitrogen only has 7. A bonding pair will experience more attraction from the oxygen’s nucleus than from nitrogen’s, and so the electronegativity of oxygen is greater.

The bonding electrons in sulfur are further away from the nucleus of the atom. When bonding electrons are further from the nucleus of the atom, there is less attraction from the nucleus.

Oxygen is more electronegative than Chlorine. Although when we move towards the right of the periodic table, electronegativity increases., but since the size of Chlorine is large, Consequently, the nucleus of oxygen attracts the electrons more than does the nucleus of chlorine.

For instance, in Mulliken scale, chlorine has a higher electronegativity than oxygen (3.3 vs. 3.0).

Iodine atom is less electronegative than chlorine atom, and chlorine is very happy with its extra electron since it is an electronegative element.

Re: F- weaker base than OH- why It’s 100% true that F- is a weaker base than OH- because of electronegativity. Having a negative charge is destabilizing, but a more electronegative atom is destabilized less by having a negative charge. In other words, a more electronegative atom is “happier” with a negative charge.

From what I understand, O has larger radius so it should be more stable (meaning less basic) than F. When they form anions, since O2− is larger, it can distribute its electrons over larger volume than F−, meaning OH− should be less basic.

In polar protic solvents (e.g. water and alcohols, any solvent with OH) nucleophilicity increases as you go down the periodic table (F- < Cl- < Br- < I – ). In polar aprotic solvents (e.g. DMSO, acetone) the order is reversed, and the most basic nucleophiles are also the most nucleophilic.

A fluoride ion has a stronger negative character than a hydroxide ion. Fluorine is more electronegative AND the oxygen in hydroxide ion is already bonded to a hydrogen. Hydrogen bonding will occur with both ions, but more so with fluoride ion.

Dimethylformamide is a polar aprotic solvent because it is a polar molecule and has no OH or NH groups. The polar C=O. and C-N bonds make the molecule polar. There are no O-H or N-H bonds, so the molecule is aprotic.

CO

The key factors that determine the nucleophile’s strength are charge, electronegativity, steric hindrance, and nature of the solvent. Nucleophilicity increases as the density of negative charge increases.

Nucleophilicity is measured by comparing reaction rates; the faster the reaction, the better (or, “stronger”) the nucleophile.

Nucleophilicity is measured by relative rates of reaction, by how rapidly an electron pair donor reacts at an atom (usually carbon) bearing a leaving group. Nevertheless, cyanide ion is a stronger nucleophile; it reacts more rapidly with a carbon bearing a leaving group than does hydroxide ion.

Take home points on electrophiles: 1) They want electrons, meaning they are electron deficient. 2) They are attacked by nucleophiles. 3) They are positively charged, polar and/or polarizable. 4) They become better electrophiles in the presence of Lewis acids.

H+ is one of the only electrophiles that is guaranteed to be an electrophile. It has no electrons, so of course, it can only accept electrons. Hence, it must be a lewis acid, or electrophile. OH− is almost always going to be a nucleophile, as it is negatively charged.