Ionic bonding occurs when atoms gain or lose valence electrons to achieve stable noble gas configurations, becoming ions. Cations are positively charged ions formed when atoms lose electrons, while anions are negatively charged ions formed when atoms gain electrons. Ionic compounds are formed from electrostatic attractions between cations and anions, resulting in electrically neutral compounds. Ionic compounds usually have high melting points and conduct electricity when molten or dissolved in water.

1. Ionic Bonding

2. Valence Electrons Number of electrons in highest occupied energy level To find the number of valence electrons = look at its group number

3. atoms tend to gain or lose electrons in order to achieve the electron configuration of a noble gas Octet Rule

4. Octet Rule = atoms tend to gain, lose or share electrons so as to have 8 electrons C would like to N would like to O would like to Gain 4 electrons Gain 3 electrons Gain 2 electrons

5. REMEMBER... Metals tend to lose their valence electrons Some nonmetals tend to gain electrons or to share with other nonmetallic elements to achieve a noble gas configuration

6. Ion Formation When an atom loses an electron it produces a positively charged ion (cation)

7. Now has full shell with similar electronic configuration to Neon (stable noble gas configuration)

8. Ion Formation The gain of negatively charged electrons by a neutral atom produces an anion. When an atom gains an electron it produces a negatively charged ion (anion)

9. Now has full shell with similar electronic configuration to Argon (stable noble gas configuration)

10. Lewis Dot Diagrams

11. Ionic Bonds Compounds composed of cations and anions are called ionic compounds . Although they are composed of ions, ionic compounds are electrically neutral . The electrostatic force that hold ions together in ionic compounds is called Ionic Bond

13. Practice, Practice, Practice Use electron dot structures to determine formulas of the ionic compounds formed when 1. potassium reacts with iodine. 2. Aluminum reacts with oxygen.

14. Properties of Ionic Compounds Most are crystalline solids at room temperature. High melting points. Conduct electricity when melted or dissolved in water .

15. Practice, Practice Write the formulas for each compound: Barium chloride Lithium oxide Magnesium oxide Calcium flouride

16. Learning Check Give the ionic charge for each of the following: A. 12 p + and 10 e - 1) 0 2) 2+ 3) 2- B. 50p + and 46 e- 1) 2+ 2) 4+ 3) 4- C. 15 p + and 18e- 2) 3+ 2) 3- 3) 5-

17. Learning Check A. Number of valence electrons in aluminum 1) 1 e - 2) 2 e - 3) 3 e - B. Change in electrons for octet 1) lose 3e - 2) gain 3 e - 3) gain 5 e - C. Ionic charge of aluminum 1) 3- 2) 5- 3) 3 +

18. Review... The number of valence electrons is the number of electrons in the outermost energy level of an atom A chemical bond is a force that holds two atoms together An ionic bond is an electrostatic force that holds a positively charged ion and a negatively charged ion together in an ionic compound Atoms are always trying to achieve stability by having a configuration of a noble gas (2 electrons in first energy level OR 8 in the outermost energy level – OCTET RULE )