lewis dots structure
Lewis Structures and the Shapes of Molecules
Pre-Lab Assignments:
To be assigned by your lab instructor.
Student Learning Outcomes:
Learn how to draw Lewis structures.
Learn how to draw Lewis structures for atoms which violate the octet rule.
Learn how to use Lewis structures and VSEPR and to predict the shapes of molecules.
Learn how to use the shape of a molecule to predict whether or not it is polar.
Experimental Goals:
The purpose of this lab is to learn how to draw Lewis structures for molecules, and, from those structures, to predict the shape of those molecules, and whether or not the molecules are polar.
Introduction:
A. Covalent Bonds and Lewis Structures
When elements combine, there are two types of bonds that may form between them:
Ionic bonds result from a transfer of electrons from one species (usually a metal) to another (usually a nonmetal or polyatomic ion).
Covalent bonds result from a sharing of electrons by two or more atoms (usually nonmetals).
Lewis theory (Gilbert Newton Lewis, 1875-1946) focuses on the valence electrons, since the outermost electrons are the ones that are highest in energy and farthest from the nucleus, and are therefore the ones that are most exposed to other atoms when bonds form.
Lewis dot diagrams for elements are a handy way of picturing valence electrons, and especially, what electrons are available to be shared in covalent bonds. The valence electrons are written as dots surrounding the symbol for the element: one dot is place on each side first, and when all four positions are filled, the remaining dots are paired with one of the first set of dots, with a maximum of two dots placed on each side. Lewis-dot diagrams of the atoms in rows 1 and 2 of the periodic table are shown below:
Unpaired electrons represent places where electrons can be gained in ionic compounds, or electrons that can be shared to form molecular compounds. (The valence electrons of helium
Pre-Lab Assignments:
To be assigned by your lab instructor.
Student Learning Outcomes:
Learn how to draw Lewis structures.
Learn how to draw Lewis structures for atoms which violate the octet rule.
Learn how to use Lewis structures and VSEPR and to predict the shapes of molecules.
Learn how to use the shape of a molecule to predict whether or not it is polar.
Experimental Goals:
The purpose of this lab is to learn how to draw Lewis structures for molecules, and, from those structures, to predict the shape of those molecules, and whether or not the molecules are polar.
Introduction:
A. Covalent Bonds and Lewis Structures
When elements combine, there are two types of bonds that may form between them:
Ionic bonds result from a transfer of electrons from one species (usually a metal) to another (usually a nonmetal or polyatomic ion).
Covalent bonds result from a sharing of electrons by two or more atoms (usually nonmetals).
Lewis theory (Gilbert Newton Lewis, 1875-1946) focuses on the valence electrons, since the outermost electrons are the ones that are highest in energy and farthest from the nucleus, and are therefore the ones that are most exposed to other atoms when bonds form.
Lewis dot diagrams for elements are a handy way of picturing valence electrons, and especially, what electrons are available to be shared in covalent bonds. The valence electrons are written as dots surrounding the symbol for the element: one dot is place on each side first, and when all four positions are filled, the remaining dots are paired with one of the first set of dots, with a maximum of two dots placed on each side. Lewis-dot diagrams of the atoms in rows 1 and 2 of the periodic table are shown below:
Unpaired electrons represent places where electrons can be gained in ionic compounds, or electrons that can be shared to form molecular compounds. (The valence electrons of helium