Physical Science Name _____________________________ Chapter 5: Types of Bonds Date____/____/____ Period_____ 1. Explain what a hydrogen bond is and draw an example. A hydrogen bond is the intermolecular forces occurring when a hydrogen atom that is bonded to a highly electronegative atom of one molecule is attracted to two unshared electrons of another molecule. It occurs between oxygen of one atom and the hydrogen of another atom. Bond are stronger within the molecule than between multiple molecules. 2. What holds bonded atoms together? Electrons 3. What is the difference between ionic and covalent compounds, including the difference between ionic and covalent bonds? Explain. Ionic compounds are between metals and nonmetals, and covalent compounds are between two nonmetals. Ionic bonds transfer electrons between the bonded atoms. This causes the melting point and boiling point of compounds to be higher. Covalent bonds share electrons between each atom in the compound. The melting point and boiling point is then lower for these compounds. 4. What type of bond allows electrons to move freely between atoms and why? Metallic bonds, because the electron clouds overlap with each other and allows the electrons to move freely between all of the electron clouds of each metal atom. 5. Explain why silver iodide, AgI, (a compound used in photography) has a much higher melting point than vanillin, C8H8O3, a sweet-smelling compound used in flavoring? AgI hase a higher melting point than vanillin because it is an ionic compound. The bonds are held more tightly together than in vanillin because it is a covalent compound. Ionic bonds have a higher melting point because the electrons are being transferred from one atom to the other. 6. Do the following compounds have ionic or covalent bonds? a. Calcium fluoride, CaF2 Ionic c. Methane, CH4 b. Nitrogen, N2 Covalent d. Copper (II) oxide, CuO Covalent Ionic 7. Which of the following will conduct electricity and why? a. Sugar, C12H22O11, dissolved in water b. Potassium hydroxide, KOH, dissolved in water. KOH because it is an ionic compound. When ionic compounds are melted or dissolved in water, it forms ions that will conduct electricity because of the electrons. 8. When placed in water, will a silver coin conduct electricity? What kind of bonds does silver have? No, because silver has metallic bonds and will not have any ions present in the solution that will conduct electricity. This is if we would test the water and not the coin itself. The coin is not going to dissolve in the water. 9. How can calcium hydroxide, Ca(OH)2 have both ionic and covalent bonds? Explain. Calcium hydroxide has both ionic and covalent compounds because hydroxide is a polyatomic ion. Polyatomic ions are bonded by covalent bonds since they are nonmetals, and then the polyatomic ion is bonded to calcium. Calcium is a metal bonded to two nonmetals, which is an ionic bond. True or False: 10. Bonds can bend and stretch. True 11. Ionic bonds conduct electricity when melted or dissolved in water. 12. Metallic bonds are formed between two nonmetals. False 13. Atoms are not able to share more than one pair of electrons. 14. Polyatomic ions are covalently bonded to each other. True False True 15. Polyatomic ions bond to other elements in order to form ionic compounds. True However, you have one positive polyatomic ion that can bond with the other polyatomics and is an exception.