1.8 Valence Electrons and Ionic Compounds

• Valence electrons are located in the outermost shell
• How can valence electrons be identified using the periodic table?

  By the group number
• How many valence electrons does Neon (Ne), in Group 18, have?

  8
• Lithium (Li), Sodium (Na), and Potassium (K) belong to Group 1
• How many valence electrons does oxygen (O) have?

  6
• What does the octet rule state about electron configuration?

  8 electrons in valence shell
• In covalent bonding, what do atoms share to form a stable bond?

  Electrons
• What are valence electrons primarily responsible for in an atom?

  Chemical properties
• Elements in Group 1 have 1 valence electron(s).
• Elements in Group 17 have 7 valence electron(s).
• The octet rule states that atoms achieve stability by having 8 electrons in their valence shell.

  True
• Which type of bonding involves the transfer of electrons to form positive and negative ions?

  Ionic bonding
• Chlorine gains an electron to form a Cl⁻ ion during ionic bonding with Sodium.

  True
• Chlorine forms the Cl⁻ ion, which is an example of an anion.
• Ionic compounds conduct electricity only when dissolved in water or in a molten state.

  True
• Ionic compounds conduct electricity when dissolved in water or molten because mobile ions carry charge.


  True
• Sodium chloride is a good conductor when dissolved in water.

  True
• The octet rule states that atoms tend to gain, lose, or share electrons to achieve a full valence shell of 8 electrons.


  True
• What is the significance of valence electrons?

  Participate in chemical reactions
• Match the group number with the number of valence electrons:

  Group 1 ↔️ 1 valence electron

  Group 2 ↔️ 2 valence electrons

  Group 15 ↔️ 5 valence electrons

  Group 17 ↔️ 7 valence electrons
• Helium (He), in Group 18, has 2 valence electrons instead of 8.

  True
• Aluminum (Al) has 3 valence electrons because it is in Group 13.


  True
• Nitrogen (N) has 5 valence electrons because it is in Group 15.


  True
• In ionic bonding, electrons are transferred
• In ionic bonding, metals form positive ions called cations
• Sodium (Na) has 1 valence electron, making it highly reactive.


  True
• Which element in Group 14 has 4 valence electrons?

  Carbon
• Which element in Group 1 has 1 valence electron?

  Lithium
• What are the two main types of bonding that follow the octet rule?

  Ionic and covalent
• In a water molecule, the oxygen atom shares 2 electrons with each hydrogen atom to achieve a full octet.
• What is a cation, and how is it formed?

  Positive ion, loses electrons
• Anions are negatively charged ions formed when atoms gain electrons.

  True
• What property of ionic compounds requires large amounts of energy to overcome strong ionic bonds?

  High melting point
• What process drives the formation of ionic compounds according to the octet rule?

  Electron transfer
• Polar solvents weaken ionic bonds through the interaction between solvent dipoles and ions
• To write formulas for ionic compounds, understanding the formation of cations and anions is crucial, as well as satisfying the octet rule.
• Steps to write ionic compound formulas:

  1️⃣ Identify the cation and anion

  2️⃣ Determine the charge on each ion

  3️⃣ Write the formula to balance charges

  4️⃣ Use the lowest whole number ratio
• In the formula for sodium chloride (NaCl), sodium has a +1 charge, while chloride has a -1 charge.
• What are valence electrons?

  Electrons in the outermost shell
• Sodium (Na) has 1 valence electron in its third shell.