8th Grade Valence Electrons Lesson Plan (Science)

Topic:Identifying the role of valence electrons in chemical properties and reactivity

Objectives & Outcome:

• Students will be able to identify the role of valence electrons in chemical properties and reactivity.

Materials

• Whiteboard or blackboard
• Markers or chalk
• Example compounds with different numbers of valence electrons (e.g. sodium chloride, sodium hydroxide, sodium acetate)
• Handouts with definitions of chemical properties and reactivity

Warm-up

• Draw a simple periodic table on the board, with a few elements listed down the left side. Ask students to brainstorm a list of properties that different elements can have (e.g. metallic, non-metallic, odorless, colorful).
• Have students place a dot next to any properties that they think are related to valence electrons.

Direct Instruction

• Review the concept of the periodic table and how it organizes elements based on their atomic number.
• Explain that the number of protons in an element is what determines its identity (e.g. carbon has six protons, and therefore is carbon).
• Valence electrons are the electrons that are present in the outermost energy level of an element. These electrons are responsible for the chemical properties of an element, including its reactivity.
• Using the simple periodic table from the warm-up, discuss examples of elements with different numbers of valence electrons (e.g. carbon has four valence electrons, while silicon has four and six).
• Discuss the concept of electron affinity, which is the amount of energy required to add a single valence electron to an element. This is related to the reactivity of an element, as elements with a high electron affinity will be more reactive than those with a low electron affinity.

Guided Practice

• Have students work in small groups to analyze the chemical properties of different elements using the information about their valence electrons and electron affinity.
• Have each group present their findings to the class and lead a discussion on the differences and similarities in reactivity and chemical properties among the elements they analyzed.

Independent Practice

• Have students choose two different elements and conduct a simple experiment to test their reactivity. For example, they could mix the two elements together and see if they form a -chemical reaction.
• Have students record their observations and make conclusions about the differences in reactivity between the two elements.
• Encourage students to use the information about valence electrons and electron affinity to explain their results.

Closure

• Review the importance of valence electrons in determining chemical properties.
• Ask students to share their observations and conclusions from the independent practice activity.

Assessment:

• Observe students during the guided practice activity to assess their understanding of the concept.
• Review and assess the group collaborative posters or presentations.