Physical Science 4-1: Electrons & Chemical Bonding

​Electrons & Chemical Bonding

Multiple Choice

Where are the nonmetals located on the periodic table? 

• Left side

• Right Side

• Center

• They are scattered throughout the table

Drag and Drop

A row on the Periodic Table of Elements is called a

Placeholder

, while a column is called a ​

Placeholder

Drag these tiles and drop them in the correct blank above

period

row

isotope

group

Multiple Choice

What is the name of group 1 on the Periodic Table?

• halogens

• noble gases

• alkali metals

• alkaline earth metals

Multiple Choice

What group number are the halogens found?

• 18

• 1

• 2

• 17

Lesson Objectives

• Describe what Chemical Bonding is

• Identify what Valence Electrons are

• Explain the role of valence electrons in Bonding

• Draw an electron dot diagram

• All Matter is made up of either individual atoms or molecules and compounds

  • Molecules and Compounds are held together by bonds

• Chemical Bonding: The Joining of atoms to form a new stable substance

• Chemical Bond: An interaction that holds atoms or ions together

  • Can act between different elements or the same type of element

• All chemical bonds form when electrons in an atom interact

​What is a Chemical Bond?

• Recall: Electrons in atoms arrange themselves in energy levels that can hold a certain number of electrons

  • Closest to the nucleus = 2 electrons

  • Every other level = 8 electrons

• We split electrons into two main groups

  • Valence Electrons: The electrons on the outermost level of an atom

  • Core Electrons: The electrons on the inner and middle levels of an atom

• Atoms are most stable when they have 8 valence electrons

  • Will react with other atoms to try and make it to 8

• The types of bonds an atom forms depend on the number of valence electrons it has.

Electrons in Atoms

Multiple Choice

The interaction between atoms or ions that holds them together is a....

• Mixture

• Compound

• Chemical Bond

• Formula

Multiple Choice

Why do elements bond?

• To be friends
• To create a new element
• To become stable
• To be bigger

Multiple Choice

Atoms are most stable when their outer shell is complete.

• true
• false

• Recall: The atomic number tells you how many protons are in an element

  • All elements are neutral, so they have to have the same number of electrons

• When you draw a diagram of the atom, the electrons on the final ring are the valence electrons

Determining the Number of Valence Electrons

• The group number of an element on the periodic table can be used to find the number of valence electrons it has

  • Elements in the same group have the same number of valence electrons

• Group 1= 1 valence electron

• Group 2= 2 Valence electrons

• Groups 13-18= Group # -10

  • Exception: Helium only has two valence electrons

Using the Periodic Table to Find Valence Electrons

• The closer an atom is to having 8 valence electrons in its outermost shell, the more likely it is to bond

  • Can get to 8 either by gaining or losing electrons

• The Noble Gases already have 8 valence electrons, so they do not form bonds at all

Why Do Atoms Bond?

Multiple Choice

What is a valence electron?

• An electron that is found in the outermost shell of an atom. 

• An electron that is found in the innermost shell of an atom.

• An electron that is found in the middle shell.

• An electron that is found in the nucleus of the atom

Multiple Choice

This is a Bohr Diagram of Aluminum. How many valence electrons does Aluminum have?

• 3

• 4

• 5

• 8

Multiple Choice

Using your Periodic Table, How many valence electrons does Lithium (Li) have?

• 8

• 1

• 5

• 2

Multiple Choice

How many valence electrons does Tin (Sn) have?

• 8

• 7

• 5

• 4

Lewis Dot Structures

• Sometimes we just want to diagram out the valence electrons in an atom

  • They are the most important in reactions

• In order to do this, we draw Lewis Dot Structures

  • Show the element Symbol with the number of Valence Electrons

Electron Dot Diagrams Practice Problem 1

• Draw the Lewis Dot Structure for the element Sodium

  • Step 1: Identify the number of Valence electrons

    • Sodium is in Group 1, so it has 1 Valence Electron

  • Step 2: Draw the Element Symbol

  • Step 3: Place the Valence electrons around the Symbol

    • Start at the top and add one to each side before doubling up

Electron Dot Diagrams Practice Problem 2

• Draw the Lewis Dot Structure for the element Fluorine

  • Step 1: Identify the number of Valence electrons

    • For Groups 13-18: Valence electrons = Group # - 10

Fill in the Blanks

Electron Dot Diagrams Practice Problem 2

• Draw the Lewis Dot Structure for the element Flourine

  • Step 1: Identify the number of Valence electrons

    • Sodium is in Group 17

      • Valence electrons = Group # - 10

  • Step 2: Draw the element Symbol

  • Step 3: Place the Valence electrons around the Symbol

    • Start at the top and add one to each side before doubling up

Electron Dot Diagrams Practice Problem 3

• Draw the Lewis Dot Structure for the element magnesium

  • Step 1: Identify the number of Valence electrons

Fill in the Blanks

Electron Dot Diagrams Practice Problem 3

• Draw the Lewis Dot Structure for the element magnesium

  • Step 1: Identify the number of Valence electrons

    • Magnesium is in group 2, so it has two valence electrons

  • Step 2: Draw the element Symbol

  • Step 3: Place the Valence electrons around the Symbol

    • Start at the top and add one to each side before doubling up

Multiple Choice

What determines the number of valence electrons an element it has.

• period/row

• group/column

• Atomic Number

• Atomic Mass

Multiple Choice

This is a correct dot diagram for nitrogen (N)

• true

• false

Multiple Choice

This is a correct dot diagram for neon (Ne)

• true

• false

Multiple Choice

Which Element could this be the dot diagram of

• P
• Ar
• Na
• B

Multiple Choice

What is the number of valence electrons needed for atoms to be stable?

• 1

• 2

• 8

• 18