Nature of Covalent Bonding Part 2: Double & Triple Covalent Bonds

Objectives Demonstrate how electron dot structures represent shared electrons Demonstrate how electron dot structures represent shared electrons Describe how atoms form double or triple covalent bonds Describe how atoms form double or triple covalent bonds

Multiple Bonds Atoms can share more than one pair of electrons in a covalent bond Atoms can share more than one pair of electrons in a covalent bond Atoms form double or triple covalent bonds if they can attain a noble gas structure by sharing two or three pairs of electrons Atoms form double or triple covalent bonds if they can attain a noble gas structure by sharing two or three pairs of electrons Sharing two pairs of electrons results in a double covalent bond Sharing two pairs of electrons results in a double covalent bond Sharing three pairs of electrons results in a triple covalent bond Sharing three pairs of electrons results in a triple covalent bond

Double Covalent Bonds

Triple Covalent Bonds

Drawing Lewis Structures with Multiple Elements 1.Draw a Lewis structure for each atom in the compound 2.Determine the number of valence electrons in the compound 3.Arrange the Lewis structure to show how the atoms bond in the molecule Halogen and hydrogen atoms often bind to only one other atom and are usually at the end of the molecule Halogen and hydrogen atoms often bind to only one other atom and are usually at the end of the molecule Carbon is often placed in the center of the molecule Carbon is often placed in the center of the molecule The atom with the lowest electronegativity is usually placed in the center The atom with the lowest electronegativity is usually placed in the center

Drawing Lewis Structures with Multiple Elements 4.Distribute the dots so that each atom except for hydrogen, beryllium, and boron, satisfies the octet rule 5.Change each pair of dots that represents a shared pair of electrons to a long dash 6.Count the number of electrons surrounding each atom making sure you satisfy the octet rule for each one (including hydrogen, beryllium, & boron) and that you have the same number of valence electrons from step 1

Examples CH 3 I H 2 S CH 2 Cl 2

Practice Problems #2 SCl 2 SiH 4 H 2 OCHF 3