Ions and Octet Rule Quiz

Ions and Octet Rule

• Atoms gain, lose, or share valence electrons to achieve a stable electron configuration similar to noble gases' octet or duet structure.
• Noble gases (He, Ne, Ar, Kr) are stable due to their filled outer electron shells (octet/duet).
• Helium (He) is stable with two valence electrons (a duet).
• Other elements achieve stability through eight valence electrons (octet).

Ionic and Covalent Bonds

• Atoms form octets to become more stable.
• They do this by losing, gaining, or sharing valence electrons.
• This process can involve forming ionic bonds (where electrons are transferred between atoms) or covalent bonds (where electrons are shared between atoms).
• Metals lose electrons, becoming positive ions (cations).
• Nonmetals gain electrons, becoming negative ions (anions).

Metals Form Positive Ions

• Metals form positive ions ("cations") by losing their valence electrons.
• The electron configuration of the cation resembles that of the nearest noble gas.
• Cations have fewer electrons than protons, resulting in a positive charge.
• Group 1 metals form 1+ ions; Group 2 metals form 2+ ions; Group 3 metals form 3+ ions.

Formation of a Sodium Ion (Na⁺)

• Sodium achieves an octet by losing its one valence electron.
• This results in a sodium ion (Na⁺) with a +1 charge.
• The sodium ion has the same electron configuration as neon.

Charge of Sodium Ion (Na⁺)

• The loss of one valence electron results in a +1 charge on the sodium ion.
• The number of protons (positive charge) is greater than the number of electrons (negative charge).

Formation of Magnesium Ion (Mg²⁺)

• Magnesium achieves an octet by losing its two valence electrons.
• This results in a magnesium ion (Mg²⁺) with a +2 charge.
• The magnesium ion has the same electron configuration as neon.

Learning Check (Questions and Answers)

• A: The number of valence electrons in aluminum is 3e⁻.
• B: The change in electrons for octet requires a loss of 3e⁻.
• C: The ionic charge of aluminum is 3⁺.
• D: The symbol for the aluminum ion is Al³⁺.

Formation of Negative Ions (Anions)

• In ionic compounds, nonmetals achieve an octet configuration by gaining electrons.
• Nonmetals gain electrons forming negatively charged ions with 1-, 2-, or 3- charges (anions).

Formation of Chloride Ion (Cl⁻)

• Chlorine achieves an octet by gaining one electron.
• This results in a chloride ion (Cl⁻) with a -1 charge.
• The Chloride ion has the same electron configuration as Argon.

Charge of Chloride Ion (Cl⁻)

• The gain of one electron results in a -1 charge on the chloride ion.
• The number of protons (positive charge) is less than the number of electrons (negative charge).

Some Ionic Charges

• This table displays common ionic charges for metals and nonmetals based on their group number. The table shows how many electrons they gain or lose to form a stable octet.

Polyatomic Ions

• Polyatomic ions are groups of atoms that have an overall ionic charge.

Names and Formulas of Common Polyatomic Ions

• This table lists common polyatomic ions, their formulas, and their names.

More Polyatomic Ions

• This table provides additional polyatomic ions, formulas, and names.