3 flourine -> fluorine
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LG Wade has put those concepts in another direction, but his explanation is valid and have put it across in the following discussion:

What makes a good leaving group?

When the C-X bond breaks in a nucleophilic substitution, the pair of electrons in the bond goes with the leaving group. In this way, the leaving group is analogous to the conjugate base in a Brønsted-Lowry acid-base reaction. (In order to act as a proton acceptor, a base must have a reactive pair of electrons)

enter image description here

Image illustrating the congujate base-conjugate acid formation

When evaluating the stability of the conjugate base that resulted from the proton transfer, basic concepts used include:

  • resonance - delocalization of electron density has a stabilizing effect, and the greater area over which the delocalization is possible, the greater the stabilization.

  • inductive effects e.g. electron withdrawing groups such as chlorine help to further spread out the electron density of the conjugate base, has a stabilizing effect.

These are the same principles when dealing with leaving groups.

In other words, the trends in basicity are parallel to the trends in leaving group potential - the weaker the base, the better the leaving group. Just as with conjugate bases, the most important question regarding leaving groups is this: when a leaving group leaves and takes a pair of electrons with it, how well is the extra electron density stabilized?

In laboratory synthesis reactions, halides often act as leaving groups. Iodide, which is the least basic of the four main halides, is also the best leaving group – it is the most stable asa negative ion. Fluoride is the least effective leaving group among the halides, because fluoride anion is the most basic.

Anomaly trend of Flourinefluorine explained

The more electronegative an atom, the better it is able to bear a negative charge. Because fluorine is the most electronegative halogen element, we might expect fluoride to also be the least basic halogen ion.

But in fact, it is the least stable, and the most basic! It turns out that when moving vertically in the periodic table, the size of the atom outdoes its electronegativity with regard to basicity. The atomic radius of iodine is approximately twice that of fluorine, so in an iodine ion, the negative charge is spread out over a significantly larger volume)

Some examples:

Chlorides, bromides, and tosylate / mesylate groups are excellent leaving groups in nucleophilic substitution reactions, due to resonance delocalization of the developing negative charge on the leaving oxygen.

enter image description here

Acknowledgements

Organic Chemistry with a Biological emphasisEmphasis (T Soderberg)

LG Wade has put those concepts in another direction, but his explanation is valid and have put it across in the following discussion:

What makes a good leaving group?

When the C-X bond breaks in a nucleophilic substitution, the pair of electrons in the bond goes with the leaving group. In this way, the leaving group is analogous to the conjugate base in a Brønsted-Lowry acid-base reaction. (In order to act as a proton acceptor, a base must have a reactive pair of electrons)

enter image description here

Image illustrating the congujate base-conjugate acid formation

When evaluating the stability of the conjugate base that resulted from the proton transfer, basic concepts used include:

  • resonance - delocalization of electron density has a stabilizing effect, and the greater area over which the delocalization is possible, the greater the stabilization.

  • inductive effects e.g. electron withdrawing groups such as chlorine help to further spread out the electron density of the conjugate base, has a stabilizing effect.

These are the same principles when dealing with leaving groups.

In other words, the trends in basicity are parallel to the trends in leaving group potential - the weaker the base, the better the leaving group. Just as with conjugate bases, the most important question regarding leaving groups is this: when a leaving group leaves and takes a pair of electrons with it, how well is the extra electron density stabilized?

In laboratory synthesis reactions, halides often act as leaving groups. Iodide, which is the least basic of the four main halides, is also the best leaving group – it is the most stable asa negative ion. Fluoride is the least effective leaving group among the halides, because fluoride anion is the most basic.

Anomaly trend of Flourine explained

The more electronegative an atom, the better it is able to bear a negative charge. Because fluorine is the most electronegative halogen element, we might expect fluoride to also be the least basic halogen ion.

But in fact, it is the least stable, and the most basic! It turns out that when moving vertically in the periodic table, the size of the atom outdoes its electronegativity with regard to basicity. The atomic radius of iodine is approximately twice that of fluorine, so in an iodine ion, the negative charge is spread out over a significantly larger volume)

Some examples:

Chlorides, bromides, and tosylate / mesylate groups are excellent leaving groups in nucleophilic substitution reactions, due to resonance delocalization of the developing negative charge on the leaving oxygen.

enter image description here

Acknowledgements

Organic Chemistry with a Biological emphasis (T Soderberg)

LG Wade has put those concepts in another direction, but his explanation is valid and have put it across in the following discussion:

What makes a good leaving group?

When the C-X bond breaks in a nucleophilic substitution, the pair of electrons in the bond goes with the leaving group. In this way, the leaving group is analogous to the conjugate base in a Brønsted-Lowry acid-base reaction. (In order to act as a proton acceptor, a base must have a reactive pair of electrons)

enter image description here

Image illustrating the congujate base-conjugate acid formation

When evaluating the stability of the conjugate base that resulted from the proton transfer, basic concepts used include:

  • resonance - delocalization of electron density has a stabilizing effect, and the greater area over which the delocalization is possible, the greater the stabilization.

  • inductive effects e.g. electron withdrawing groups such as chlorine help to further spread out the electron density of the conjugate base, has a stabilizing effect.

These are the same principles when dealing with leaving groups.

In other words, the trends in basicity are parallel to the trends in leaving group potential - the weaker the base, the better the leaving group. Just as with conjugate bases, the most important question regarding leaving groups is this: when a leaving group leaves and takes a pair of electrons with it, how well is the extra electron density stabilized?

In laboratory synthesis reactions, halides often act as leaving groups. Iodide, which is the least basic of the four main halides, is also the best leaving group – it is the most stable asa negative ion. Fluoride is the least effective leaving group among the halides, because fluoride anion is the most basic.

Anomaly trend of fluorine explained

The more electronegative an atom, the better it is able to bear a negative charge. Because fluorine is the most electronegative halogen element, we might expect fluoride to also be the least basic halogen ion.

But in fact, it is the least stable, and the most basic! It turns out that when moving vertically in the periodic table, the size of the atom outdoes its electronegativity with regard to basicity. The atomic radius of iodine is approximately twice that of fluorine, so in an iodine ion, the negative charge is spread out over a significantly larger volume)

Some examples:

Chlorides, bromides, and tosylate / mesylate groups are excellent leaving groups in nucleophilic substitution reactions, due to resonance delocalization of the developing negative charge on the leaving oxygen.

enter image description here

Acknowledgements

Organic Chemistry with a Biological Emphasis (T Soderberg)

2 Grammar and revision
source | link

LG Wade has put thos conceptthose concepts in another direction, but his explanation is valid and have put it across in the following discussion n:

What makes a good leaving group?

When the C-X bond breaks in a nucleophilic substitution, the pair of electrons in the bond goes with the leaving group. In this way, the leaving group is analogous to the conjugate base in a Brønsted-Lowry acid-base reaction. (In order to act as a proton acceptor, a base must have a reactive pair of electrons)

enter image description here

Image illustrating the congujate base-conjugate acid formation

When evaluating the stability of the conjugate base that resulted from the proton transfer, basic concepts used include:

  • resonance - delocalization of electron density has a stabilizing effect, and the greater area over which the delocalization is possible, the greater the stabilization.

  • inductive effects e.g. electron withdrawing groups such as chlorine help to further spread out the electron density of the conjugate base, has a stabilizing effect.

These are the same principles when dealing with leaving groups.

In other words, the trends in basicity are parallel to the trends in leaving group potential - the weaker the base, the better the leaving group. Just as with conjugate bases, the most important question regarding leaving groups is this: when a leaving group leaves and takes a pair of electrons with it, how well is the extra electron density stabilized?

In laboratory synthesis reactions, halides often act as leaving groups. Iodide, which is the least basic of the four main halides, is also the best leaving group – it is the most stable asa negative ion. Fluoride is the least effective leaving group among the halides, because fluoride anion is the most basic.

Anomaly trend of Flourine explained

The more electronegative an atom, the better it is able to bear a negative charge. Because fluorine is the most electronegative halogen element, we might expect fluoride to also be the least basic halogen ion.

But in fact, it is the least stable, and the most basic! It turns out that when moving vertically in the periodic table, the size of the atom outdoes its electronegativity with regard to basicity. The atomic radius of iodine is approximately twice that of fluorine, so in an iodine ion, the negative charge is spread out over a significantly larger volume)

Some examples:

Chlorides, bromides, and tosylate / mesylate groups are excellent leaving groups in nucleophilic substitution reactions, due to resonance delocalization of the developing negative charge on the leaving oxygen.

enter image description here

Acknowledgements

Organic Chemistry with a Biological emphasis (T Soderberg)

LG Wade has put thos concept in another direction, but his explanation is valid and have put it across in the following discussion n

What makes a good leaving group?

When the C-X bond breaks in a nucleophilic substitution, the pair of electrons in the bond goes with the leaving group. In this way, the leaving group is analogous to the conjugate base in a Brønsted-Lowry acid-base reaction. (In order to act as a proton acceptor, a base must have a reactive pair of electrons)

enter image description here

When evaluating the stability of the conjugate base that resulted from the proton transfer, basic concepts used include:

  • resonance - delocalization of electron density has a stabilizing effect, and the greater area over which the delocalization is possible, the greater the stabilization.

  • inductive effects e.g. electron withdrawing groups such as chlorine help to further spread out the electron density of the conjugate base, has a stabilizing effect.

In other words, the trends in basicity are parallel to the trends in leaving group potential - the weaker the base, the better the leaving group. Just as with conjugate bases, the most important question regarding leaving groups is this: when a leaving group leaves and takes a pair of electrons with it, how well is the extra electron density stabilized?

In laboratory synthesis reactions, halides often act as leaving groups. Iodide, which is the least basic of the four main halides, is also the best leaving group – it is the most stable asa negative ion. Fluoride is the least effective leaving group among the halides, because fluoride anion is the most basic.

Anomaly trend of Flourine explained

The more electronegative an atom, the better it is able to bear a negative charge. Because fluorine is the most electronegative halogen element, we might expect fluoride to also be the least basic halogen ion.

But in fact, it is the least stable, and the most basic! It turns out that when moving vertically in the periodic table, the size of the atom outdoes its electronegativity with regard to basicity. The atomic radius of iodine is approximately twice that of fluorine, so in an iodine ion, the negative charge is spread out over a significantly larger volume)

Some examples:

Chlorides, bromides, and tosylate / mesylate groups are excellent leaving groups in nucleophilic substitution reactions, due to resonance delocalization of the developing negative charge on the leaving oxygen.

enter image description here

Acknowledgements

Organic Chemistry with a Biological emphasis (T Soderberg)

LG Wade has put those concepts in another direction, but his explanation is valid and have put it across in the following discussion:

What makes a good leaving group?

When the C-X bond breaks in a nucleophilic substitution, the pair of electrons in the bond goes with the leaving group. In this way, the leaving group is analogous to the conjugate base in a Brønsted-Lowry acid-base reaction. (In order to act as a proton acceptor, a base must have a reactive pair of electrons)

enter image description here

Image illustrating the congujate base-conjugate acid formation

When evaluating the stability of the conjugate base that resulted from the proton transfer, basic concepts used include:

  • resonance - delocalization of electron density has a stabilizing effect, and the greater area over which the delocalization is possible, the greater the stabilization.

  • inductive effects e.g. electron withdrawing groups such as chlorine help to further spread out the electron density of the conjugate base, has a stabilizing effect.

These are the same principles when dealing with leaving groups.

In other words, the trends in basicity are parallel to the trends in leaving group potential - the weaker the base, the better the leaving group. Just as with conjugate bases, the most important question regarding leaving groups is this: when a leaving group leaves and takes a pair of electrons with it, how well is the extra electron density stabilized?

In laboratory synthesis reactions, halides often act as leaving groups. Iodide, which is the least basic of the four main halides, is also the best leaving group – it is the most stable asa negative ion. Fluoride is the least effective leaving group among the halides, because fluoride anion is the most basic.

Anomaly trend of Flourine explained

The more electronegative an atom, the better it is able to bear a negative charge. Because fluorine is the most electronegative halogen element, we might expect fluoride to also be the least basic halogen ion.

But in fact, it is the least stable, and the most basic! It turns out that when moving vertically in the periodic table, the size of the atom outdoes its electronegativity with regard to basicity. The atomic radius of iodine is approximately twice that of fluorine, so in an iodine ion, the negative charge is spread out over a significantly larger volume)

Some examples:

Chlorides, bromides, and tosylate / mesylate groups are excellent leaving groups in nucleophilic substitution reactions, due to resonance delocalization of the developing negative charge on the leaving oxygen.

enter image description here

Acknowledgements

Organic Chemistry with a Biological emphasis (T Soderberg)

1
source | link

LG Wade has put thos concept in another direction, but his explanation is valid and have put it across in the following discussion n

What makes a good leaving group?

When the C-X bond breaks in a nucleophilic substitution, the pair of electrons in the bond goes with the leaving group. In this way, the leaving group is analogous to the conjugate base in a Brønsted-Lowry acid-base reaction. (In order to act as a proton acceptor, a base must have a reactive pair of electrons)

enter image description here

When evaluating the stability of the conjugate base that resulted from the proton transfer, basic concepts used include:

  • resonance - delocalization of electron density has a stabilizing effect, and the greater area over which the delocalization is possible, the greater the stabilization.

  • inductive effects e.g. electron withdrawing groups such as chlorine help to further spread out the electron density of the conjugate base, has a stabilizing effect.

In other words, the trends in basicity are parallel to the trends in leaving group potential - the weaker the base, the better the leaving group. Just as with conjugate bases, the most important question regarding leaving groups is this: when a leaving group leaves and takes a pair of electrons with it, how well is the extra electron density stabilized?

In laboratory synthesis reactions, halides often act as leaving groups. Iodide, which is the least basic of the four main halides, is also the best leaving group – it is the most stable asa negative ion. Fluoride is the least effective leaving group among the halides, because fluoride anion is the most basic.

Anomaly trend of Flourine explained

The more electronegative an atom, the better it is able to bear a negative charge. Because fluorine is the most electronegative halogen element, we might expect fluoride to also be the least basic halogen ion.

But in fact, it is the least stable, and the most basic! It turns out that when moving vertically in the periodic table, the size of the atom outdoes its electronegativity with regard to basicity. The atomic radius of iodine is approximately twice that of fluorine, so in an iodine ion, the negative charge is spread out over a significantly larger volume)

Some examples:

Chlorides, bromides, and tosylate / mesylate groups are excellent leaving groups in nucleophilic substitution reactions, due to resonance delocalization of the developing negative charge on the leaving oxygen.

enter image description here

Acknowledgements

Organic Chemistry with a Biological emphasis (T Soderberg)