11.5 Reaction Mechanisms

Question 1

What is heterolytic fission?

Answer 1

When a covalent bond breaks and one of the bonded atoms takes both the electrons from the bond

Question 2

When does heterolytic fission usually occur?

Answer 2

When the electronegativity difference between the two atoms or compounds is large

Question 3

What is homolytic fission?

Answer 3

When a covalent bond breaks and each of the bonded atoms takes one of the shared pair of electrons from the bond
Each atom has an impaired electron

Question 4

When does homolytic fission generally occur?

Answer 4

When the electronegativity is similar or the same

Question 5

What is a radical? How is it represented?

Answer 5

An at I’m of group of atoms with an unpaired electron
Dot next to compound

Question 6

What do curly arrows show?

Answer 6

Movement of electrons

Question 7

What are the conditions for drawing curly arrows?

Answer 7

• must begin at a lone pair electron on an atom
  OR
• must begin from a bind that is about the be broken
• should point at a new bond forming (an atom that will share electrons
  OR
• point at atoms taking both electrons from a bond and gaining a lone pair

Question 8

How do you represent the moving of electrons in homolytic fission of the same element? H - H:

Answer 8

Draw a half arrow to each atom to show one electron going to each element

Question 9

What are the 3 types of reactions? Short description:

Answer 9

Addition reaction - adding more molecules, 2 reactants join to form 1 product
Substitution - replacing one molecule for another
Elimination - removing a small molecule from a larger one