2 What are Lewis Structures? Simplified Bohr diagrams which only consider electrons in outer energy levels.The Lewis structure consists of the element symbol surrounded by “dots” to represent the number of electrons in the outer energy level.
3 What is a valence electron? A valence electron is an electron in the outer shell of the atom.An electron in the outer shell of an atom that can be lost to or shared with another atom to form a molecule.Molecules will be discussed later when learning chemical reactions.
4 How are Lewis Structures and Bohr Models Alike? They both represent the number of electrons on the valence shell – the outer shellThe Lewis structure is more simple than the Bohr model
5 How are Lewis Structures and Bohr Models Different? The Bohr model places electrons in energy levels (represented by rings) around the nucleusThe Lewis structure places the electrons around the chemical symbol. The number of valence electrons is placed in a square design.
6 Lewis Structures Find your element on the periodic table. Determine the number of electrons in the last shell. This is called the valence shellThis is how many electrons you will draw.
7 Lewis Structures Find out which group (column) your element is in. This will tell you the number of valence electrons your element has.You will only draw the valence electrons.
8 Groups - Review Group 8 = 8 electrons Group 1 = 1 electron Except for He, it has 2 electronsGroup 2 = 2 electronsEach column is called a “group”3, 4, 5, 6, 7Each element in a group has the same number of electrons in their outer orbital, also known as “shells”.The electrons in the outer shell are called “valence electrons”
9 C Lewis Structures Write the element symbol. Carbon is in the 14th group, so it has 4 valence electrons.Starting at the right, draw 4 electrons, or dots, counter-clockwise around the element symbol.C
10 C Lewis Structures Check your work. Using your periodic table, check that Carbon is in the 4th group.You should have 4 total electrons, or dots, drawn in for Carbon.C