Objective Utilize & apply the Periodic Table to diagram Bohr Models and Lewis Dot Diagrams. Main Ideas 1. Energy Levels 2. Bohr Modeling 3. Valence Electrons 4. Octet Rule 5. Lewis Dot Diagrams Bohr Modeling & Lewis Dot Diagrams IAN pg. 23 Don't find fault, find a remedy. - Henry Ford

University of Utah Cell Scale and Size 2

I. Bohr Modeling A. Atomic number = protons & electrons a neutral atom has. B. Electrons found in energy levelsor shells. 1. Energy levels or shells hold a maximum number of electrons.

Energy Level Total # ofTotal Or Shell electrons / shell Combined 1 2 (1)2 2 8 (2) (3) (4) (5) (6)114+ Sublevels: s,p,d,f,g,h Indicates the number of electrons/energy level

Chemical Symbol: Na (Sodium) At #_11_ At Weight_23_ Protons = _11_ Electrons _11_ Neutrons = _12_ (At W – At #) Energy Shells or Levels = _3_ (See Energy Level Chart IAN pg. 53) 11P 12N Bohr Model Example

II. Lewis Dot Structures A. “Dot Models” are used to represent Valence Shell electrons B. Gilbert Newton Lewis American Chemist discovered covalent bond

C. The electrons in the outer most energy level are called valence electrons. D. Atomic Stability depends on filling the valence shell with electrons = Octet Rule 1. This is why specific atoms will bond with other atoms. Ex. H 2 O

Shared Electrons Hydrogen Hydrogen Oxygen

Periodic table groupValence electrons Group 1 (I) (alkali metals)alkali metals 1 Group 2 (II) (alkaline earth metals)alkaline earth metals 2 Groups 3-12 (transition metals)transition metals ******* Group 13 (III) (boron group)boron group 3 Group 14 (IV) (carbon group)carbon group 4 Group 15 (V) (nitrogen group)nitrogen group 5 Group 16 (VI) (chalcogens)chalcogens 6 Group 17 (VII) (halogens)halogens 7 Group 18 (VIII or 0) (noble gases)noble gases 8** Think of Valence electrons as “free electrons” They are “free” to move or free to be shared.

Groups - Review Each column is called a “group” Each element in a group has the same number of electrons in their outer energy level. Except for He, it has 2 electrons The electrons in the outer energy levels are called “valence electrons”

1. Write the element symbol. 2. Locate the group (1 – 8) This is the # of valence electrons. 3. Follow this diagram for placing electrons as “Dots” in order. Copy this down E.Drawing Lewis Dot Structures

IaN pg. 22 Periodic Table of Elements Handout. Glue Down!

1)Element Symbol 2)4 th group. 3)You should have 4 total electrons, or dots, drawn in for Carbon. Lewis Dot Structures Example A

Lewis Dot Structures

1)Element Symbol 2)1 st group. 3)You should have 1 total electron, or dot, drawn in for Hydrogen.

Lewis Structures 1)Element Symbol 2)15 th group. 3)You should have 5 total electrons, or dots, drawn in for Phosphorous.

Lewis Structures 1)Element Symbol 2)2 nd group. 3)You should have 2 total electrons, or dots, drawn in for Calcium.

Lewis Structures

What do all of these Atoms have in common? Look closely… They all have 1 valence electron….. In an attempt to be more stable they give up their electron, becoming a positive ion. (Cation)

What do all of these Atoms have in common? Look closely… They all have 7 valence electron….. In an attempt to be more stable they give take an electron, becoming a negative ion. (Anion)

What do all of these Atoms have in common? Look closely… They all have their outer energy levels full….. Noble gases are the most stable atoms.

What element is this? How many Valence electrons does it have? Does it want to gain or lose electrons to get more stable? Is it a Cation or Anion?

What element is this? How many Valence electrons does it have? Does it want to gain or lose electrons to get more stable? Is it a Cation or Anion?

What element is this? How many Valence electrons does it have? Does it want to gain or lose electrons to get more stable? Is it a Cation or Anion ?