Valence Electrons and Reactivity

The video tutorial introduces the concept of valence electrons and their role in determining the reactivity and stability of elements. It explains energy levels and uses neon and chlorine as examples to demonstrate how to count valence electrons. The tutorial emphasizes that elements with eight valence electrons are stable, while those with one or seven are reactive. Students are guided through exercises to reinforce these concepts.

What determines the reactivity of an atom?

• The number of protons

• The number of valence electrons

• The number of neutrons

• The atomic mass

How many energy levels does neon have?

• Four

• Three

• Two

• One

What is the maximum number of electrons that can be held in the outer shell of an atom?

• Six

• Nine

• Eight

• Seven

An atom is considered stable when it has how many valence electrons?

• One

• Four

• Six

• Eight

Which of the following indicates a reactive element?

• Eight valence electrons

• Four valence electrons

• Zero valence electrons

• One or seven valence electrons

How many valence electrons does chlorine have?

• Eight

• Six

• Five

• Seven

What does having seven valence electrons mean for an element's reactivity?

• It is reactive

• It is inert

• It is neutral

• It is stable

Which shell is considered when determining the valence electrons?

• The innermost shell

• The second shell

• The outermost shell

• The third shell

What happens when an atom has a full outer shell?

• It becomes reactive

• It becomes stable

• It loses electrons

• It becomes unstable

What is the significance of having one valence electron?

• The atom is inert

• The atom is neutral

• The atom is reactive

• The atom is stable