Bonding Basics
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This document provides an overview of bonding basics, including ionic and covalent bonds. Ionic bonds form when a metal transfers electrons to a nonmetal, resulting in oppositely charged ions that attract. Covalent bonds form when atoms share electrons to achieve a full outer shell. Examples show Lewis diagrams and representing the transfer or sharing of electrons to form ionic compounds like KI or covalent molecules like H2O.
Bonding Basics
- 1. Bonding Basics It’s really very easy!
- 2. Before you can figure out how atoms form molecules and compounds, you need some information. You need to be able to figure out all this from the periodic table. Total # of # of Valence # of Electrons Oxidation Element Atomic Symbol Electrons1 Electrons2 gained or lost3 Number4 Iodine I 53 17 gain 1 -1 Lithium Li 3 1 lose 1 +1 Calcium Ca 20 2 lose 2 +2 Sulfur S 16 6 gain 2 -2 Boron B 5 3 lose 3 +3 Silicon Si 14 4 gain/lose 4 + 4 or - 4 Phosphorus P 15 5 gain 3 -3 1. Total number of electrons equals the atomic number. 2. The number of valence electrons is the same as the column number on the periodic table 3. Less that 4 valence electrons, electrons are lost. More than 4 valence electrons, electrons are gained. Atoms with 4 (carbon, silicon) can gain or lose. 4. Atoms lose electrons to become positive ions. Atoms gain electrons to become negative ions.
- 3. Ionic Bonds • Form when one atom loses electrons and one atom gains electrons. • Always form between a metal and a nonmetal. (never between two nonmetals) • The oxidation numbers must add up to zero.
- 4. Example 1. Potassium + Iodine First, write the Lewis Diagram for each element. K I
- 5. Example 1. Potassium + Iodine Next, draw an arrow showing the transfer of electrons from one atom to the other. K I
- 6. Example 1. Potassium + Iodine Now, show the charges on the newly formed ions. Potassium lost an electron to become +1, and Iodine gained an electron to become -1. K+ I -
- 7. Example 1. Potassium + Iodine Finally, combine the 2 ions to form the final compound. K+ + I- KI
- 8. Example 2. Magnesium + Oxygen First, write the Lewis Diagram for each element. Mg O
- 9. Example 2. Magnesium + Oxygen Next, draw an arrow showing the transfer of electrons from one atom to the other. Mg O
- 10. Example 2. Magnesium + Oxygen Now, show the charges on the newly formed ions. Magnesium lost 2 electrons to become +2, and Oxygen gained 2 electrons to become -2. Mg2+ O2-
- 11. Example 2. Magnesium + Oxygen Finally, combine the 2 ions to form the final compound. Mg2+ +O2- MgO
- 12. Example 3. Lithium + Nitrogen First, write the Lewis Diagram for each element. Li N
- 13. Example 3. Lithium + Nitrogen Next, draw an arrow showing the transfer of electrons from one atom to the other. Notice that 1 Lithium does not provide enough electrons, so add more. Li N
- 14. Example 3. Lithium + Nitrogen A second Lithium atom provides another electron, still leaving Nitrogen 1 short. So, add another. Li N
- 15. Example 3. Lithium + Nitrogen Nitrogen now has eight valence electrons. It took 3 Lithium atoms to provide enough electrons to fill Nitrogen’s valence energy level. Li N
- 16. Example 3. Lithium + Nitrogen Now, show the charges on the newly formed ions. Lithium lost 1 electron to become +1, and Nitrogen gained 3 electrons to become -3. Li + N3-
- 17. Example 3. Lithium + Nitrogen Finally, combine the newly formed ions to make the compound. Li ++ Li ++ Li ++ N3- Li3N
- 18. Covalent Bonds • Form when one atom shares electrons with another atom. • Always form between between two nonmetals. • The oxidation numbers must add up to zero.
- 19. Example 1. Fluorine + Fluorine First, write the Lewis Diagram for each element. F F
- 20. Example 1. Fluorine + Fluorine Next, draw circles showing the electrons that are shared. F F
- 21. Example 1. Fluorine + Fluorine Finally, draw a line showing the bond between the atoms and then write the formula. F F F2
- 22. Example 2. 3 Hydrogen + Phosphorus First, write the Lewis Diagram for each element. H H P H
- 23. Example 2. 3 Hydrogen + Phosphorus Next, draw circles showing the electrons that are shared. H HP H
- 24. Example 2. 3 Hydrogen + Phosphorus Finally, draw lines showing the bond between the atoms and then write the formula. H HP H3P H
- 25. Example 3. 2 Hydrogen + Sulfur First, write the Lewis Diagram for each element. H H S
- 26. Example 3. 2 Hydrogen + Sulfur Next, draw circles showing the electrons that are shared. H HS
- 27. Example 3. 2 Hydrogen + Sulfur Finally, draw lines showing the bond between the atoms and then write the formula. H HS H2S