1. Ionic Bonds During ionic bonding, 1 or more valence electrons are transferred from one atom to another. Atoms are usually neutral because they have the same # of protons as they do electrons. However, a transfer of electrons between atoms changes the number of electrons in each atom, thus creating a charged particle or “ion”

2. Forming positive ions Ionic bonds form during chemical changes when atoms pull electrons away from other atoms. Atoms that lose electrons end up having a positive charge. Metal atoms have few valence electrons and typically lose these valence electrons and form positive ions.

3. Energy It requires energy to pull electrons away from an atom.

4. Answers to “directed reading B” 1. A- SUGAR 2. A- CHEMICAL BONDING 3. B- CHEMICAL BOND 4.C- ELECTRONS 5.D- MODELS 6. C- 6 7. ATOMIC NUMBER 8. GROUP

5. 9. VALENCE ELECTRONS 10. B- NUMBER OF VALENCE ELECTRONS 11. D- GROUP 18

6. Welcome Work: “Chemical Compounds” In your science notebook, identify the elements in the following compounds and predict whether the compounds are similar to each other and why. Try to guess the identities of the compounds. 1. C₆H₁₂O₆ 2. C₂H₅OH 3. C₆H₈O₆ 4. C₆H₈O₇ In your science notebook, identify the elements in the following compounds and predict whether the compounds are similar to each other and why. Try to guess the identities of the compounds. 1. C₆H₁₂O₆ 2. C₂H₅OH 3. C₆H₈O₆ 4. C₆H₈O₇

7. C₆H₁₂O₆ 6 Carbons 12 Hydrogens 6 Oxygens What is it? Glucose (a sugar) Glucose is one of the products of photosynthesis in plants.photosynthesis plants In animals, glucose is synthesized in the liver and kidneys.liver kidneys Glucose is produced commercially via starch. Many crops can be used as the source of starch: Maize, rice, wheat, potato. In the United States, cornstarch (from maize) is used almost exclusively.starchMaize ricewheatpotatoUnited Statescornstarch 6 Carbons 12 Hydrogens 6 Oxygens What is it? Glucose (a sugar) Glucose is one of the products of photosynthesis in plants.photosynthesis plants In animals, glucose is synthesized in the liver and kidneys.liver kidneys Glucose is produced commercially via starch. Many crops can be used as the source of starch: Maize, rice, wheat, potato. In the United States, cornstarch (from maize) is used almost exclusively.starchMaize ricewheatpotatoUnited Statescornstarch

8. C₂H₅OH 2 Carbons 6 Hydrogens 1 Oxygen What is it? Ethyl Alcohol ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a flammable, colorless liquid. It is a psychoactive drug, best known as the type of alcohol found in alcoholic beverages.flammablepsychoactive drugalcoholalcoholic beverages 2 Carbons 6 Hydrogens 1 Oxygen What is it? Ethyl Alcohol ethyl alcohol, pure alcohol, grain alcohol, or drinking alcohol, is a flammable, colorless liquid. It is a psychoactive drug, best known as the type of alcohol found in alcoholic beverages.flammablepsychoactive drugalcoholalcoholic beverages

9. C₆H₈O₆ 6 Carbons 8 Hydrogens 6 Oxygens What is it? Vitamin C Vitamin C or ascorbic acid is an essential nutrient for a large number of higher primate species (including humans).essential nutrienthigher primate The presence of ascorbate is required for a range of essential metabolic reactions in all animals. It is made internally by almost all organisms, humans being a notable exception.metabolic reactionsmade internallyhumans 6 Carbons 8 Hydrogens 6 Oxygens What is it? Vitamin C Vitamin C or ascorbic acid is an essential nutrient for a large number of higher primate species (including humans).essential nutrienthigher primate The presence of ascorbate is required for a range of essential metabolic reactions in all animals. It is made internally by almost all organisms, humans being a notable exception.metabolic reactionsmade internallyhumans

10. C₆H₈O₇ 6 Carbons 8 Hydrogens 7 Oxygens What is it? Citric Acid It is a natural preservative and is also used to add an acidic, or sour, taste to foods and soft drinks. In biochemistry, it is important as an intermediate in the citric acid cycle and therefore occurs in the metabolism of almost all living things.preservativesoft drinksbiochemistrycitric acid cycle metabolismliving things Citric acid exists in a variety of fruits and vegetables, most notably citrus fruits: Lemons and limes.fruitscitrus fruitsLemonslimes 6 Carbons 8 Hydrogens 7 Oxygens What is it? Citric Acid It is a natural preservative and is also used to add an acidic, or sour, taste to foods and soft drinks. In biochemistry, it is important as an intermediate in the citric acid cycle and therefore occurs in the metabolism of almost all living things.preservativesoft drinksbiochemistrycitric acid cycle metabolismliving things Citric acid exists in a variety of fruits and vegetables, most notably citrus fruits: Lemons and limes.fruitscitrus fruitsLemonslimes

11. Ch.13 Section 2 Explain how Ionic Bonds Form Describe how positive ions form Describe how negative ions form Explain why ionic compounds are neutral

12. Forming Negative Ions Some atoms gain electrons from other atoms during chemical changes. These ions have a negative charge because they have more electrons than they do protons. Some atoms gain electrons from other atoms during chemical changes. These ions have a negative charge because they have more electrons than they do protons.

13. Nonmetal Atoms Gain Electrons The outer most energy level of nonmetals is almost full. So, they tend to gain electrons from other atoms making them a “negative ion” The outer most energy level of nonmetals is almost full. So, they tend to gain electrons from other atoms making them a “negative ion”

14. Energy of gaining electrons Energy is given off by most nonmetal atoms when they gain electrons The more easily an atom gains an electron, the more energy the atom releases. Energy is given off by most nonmetal atoms when they gain electrons The more easily an atom gains an electron, the more energy the atom releases.

15. Ch.13 Section 3 Student objectives – Explain how covalent bonds form – Describe molecules – Explain how metallic bonds form – Describe the properties of metals Student objectives – Explain how covalent bonds form – Describe molecules – Explain how metallic bonds form – Describe the properties of metals

16. Vocab Make sure you have the following vocabulary defined in your SNB glossary: – Covalent bond – Molecule – Metallic bond Make sure you have the following vocabulary defined in your SNB glossary: – Covalent bond – Molecule – Metallic bond

17. Covalent bonds Most things are held together by covalent bonds (Ex: water, sugar, wood) Covalent bond substances have low melting and boiling points and are brittle Are formed by the SHARING OF ELECTRONS Most things are held together by covalent bonds (Ex: water, sugar, wood) Covalent bond substances have low melting and boiling points and are brittle Are formed by the SHARING OF ELECTRONS

18. Covalent bonds and molecules Substances containing covalent bonds consist of individual particles called molecules Most molecules are combined of 2 or more elements A molecule is the smallest particle into which a covalently bonded compound can be divided and still be the same compound Substances containing covalent bonds consist of individual particles called molecules Most molecules are combined of 2 or more elements A molecule is the smallest particle into which a covalently bonded compound can be divided and still be the same compound

19. Answers to Directed Reading B Ch.13 section 2 1. B. ionic bond 2. A. ions 3. A. bc the # of electrons changes 4. B. + 1 5. C. Na⁺ 6. ion 7. energy 1. B. ionic bond 2. A. ions 3. A. bc the # of electrons changes 4. B. + 1 5. C. Na⁺ 6. ion 7. energy

20. 8. positive ions 9. valence electrons 10. negative ions 8. positive ions 9. valence electrons 10. negative ions