Unit 11: Ionic & Metallic Bonding (Chapter 7) 1 Unit 11: Covalent Bonding (Chapter 8) 2 Unit 11 ~ Problem Set #1 Read pg. 187-199. Pg. 193; 7.1 Section Assessment #9, 10, 11 9. How many electrons will each element gain or lose in forming an ion? a. Calcium - _____________________ b. Fluorine - _____________________ c. Aluminum - _____________________ d. Oxygen - _____________________ 10. Write the name and symbol of the ion formed when a. a potassium atom loses one electron ________________________________ b. a zinc atom loses two electrons ________________________________ c. a fluorine atom gains one electron _________________________________ 11. Write the electron configuration of Cd+2. ___________________________________________ Pg. 196; practice problems #12, 13 12. Use electron dot structures to determine formulas of the ionic compounds formed when a. potassium reacts with iodine. 13. What is the formula of the ionic compound composed of calcium cations and chloride anions? __________________ 3 Pg. 199; 7.2 Section Assessment #15, 16, 18, 20, 22 15. What properties characterize ionic compounds? ______________________________________ _________________________________________________________________________________ 16. Define an ionic bond. _____________________________________________________________ _________________________________________________________________________________ 18. Write the correct chemical formula for the compounds formed from each pair of ions. a. K+, S-2 _____________________________ b. Ca+2, O-2 _____________________________ c. Na+, O-2 _____________________________ d. Al+3, N-3 _____________________________ 20. Which pairs of elements are likely to form ionic compounds? a. Cl, Br _____________________________ b. Li, Cl _____________________________ c. K, He _____________________________ d. I, Na _____________________________ 22. Why do ionic compounds conduct electricity when they are melted or dissolved in water? ________________________________________________________________________________ ________________________________________________________________________________ 4 Bonding Pre-Quiz 1. Answer the following questions about the element, arsenic, Z=33. a. Write the longhand spectroscopic notation for this METALLOID. b. Draw its shorthand orbital notation diagram. c. How many valence electrons does arsenic have? _____________________________ d. Draw its Lewis dot structure. e. Predict the 3 ions this METALLOID makes. ___________________________________ f. Draw the Lewis dot structures for the three ions. 2. What types of elements make up an ionic compound? Give two examples. ____________ ______________________________________________________________________________ 3. What types of elements make up a molecular compound? Give two examples. ________ ______________________________________________________________________________ 4. a. What is the most electronegative element? __________________________________ b. Define electronegativity.___________________________________________________ ______________________________________________________________________________ 5. a. What are the names of the two types of ions? _______________________________ b. How is each one formed? _________________________________________________ ______________________________________________________________________________ c. Give two examples of each. ______________________________________________ 6. What does every element strive for? _____________________________________________ 5 6 Electron Arrangement and Bonding Video Questions Video 1: How Atoms Bond 1. Nuclei and electrons, both within atoms and between atoms, exert ___________________________ forces on each other, while two nuclei or two electrons of adjacent atoms exert _______________________________ forces on each other. 2. T-F: In the H—H bond, the electrons are always found in the same place. ______________________ 3. Bonds in which atoms share electrons are called _______________________________ bonds. 4. The reason two helium atoms do not bond together is because the forces of __________________________ are greater than the forces of _______________________________, leaving the helium atoms far apart. 5. The family of atoms which normally do not bond together are called the _____________________. 6. There are two reasons why sodium’s 3s electron is held quite loosely by the nucleus. 1) This outer electron is located far from the nucleus, thus decreasing its ______________________________ to the nucleus, and 2) the atom’s other ten electrons _______________________________ the outer electron, which _______________________________ its attraction to the nucleus. 7. Atoms shrink across a period because of increasing _______________________________ charge. 8. In a bond between sodium and chlorine, an electron is _______________________________ to chlorine, resulting in the formation of ions for both sodium and chlorine. 9. The name given to the type of bond between sodium and chlorine, in which an electron is transferred, is an ______________________________ bond. Video 2: Molecular Substances and Covalent Crystals 1. In the Cl—Cl bond, the atoms share _______________ pair of electrons to make a single covalent bond. 2. In the O—O bond, each atom must gain _______________ electrons to acquire the electron configuration of neon. 3. Thus, in the diatomic element oxygen, there are _______________ shared pairs of electrons in their molecules, creating a _______________________________ covalent bond. 4. Diatomic nitrogen atoms share _______________ pairs of electrons in their molecules, creating a _____________________covalent bond. 5. T-F: The strength of covalent bonds varies as follows: Triple > Double > Single _______________________________ 6. In the HCl molecule, _______________________________ has a stronger attraction for electrons, thus the electrons spend most of their time there. 7. A molecule in which partially positive and partially negative charges exists is called ____________. 8. T-F: Polar molecules have higher boiling and melting points than nonpolar molecules. _________ 7 9. Carbon can form up to _______________________________ single covalent bonds. 10. T-F: In general, the larger the molecule, the higher the melting and boiling points. ____________ 11. Molecules such as diamond are called _______________________ ___________________________. Video 3: Metals and Ionic Solids 1. T-F: In metals, electrons are free to move from atom to atom. _______________________________ 2. Many metals have similar electron configurations. Their outer electrons are located in a(n) ________ orbital. 3. As a result of the location of the outer electrons, a bond can form in ________________ direction and are ________________ held by the nucleus, which means that the electrons can come under the influence of an _____________________________ atom. 4. The atoms in a metallic bond behave like a series of _____________________ positive charges in a ____________________ of free flowing electrons. 5. The “free to move” idea of electrons in metals explains a metal’s ability to conduct both ______________________ and _______________________________ . 6. Metallic bonds are ______________ directional, so the atoms can ________________________ over each another. This makes it possible to press metals into thin ____________________ and stretch into thin ____________________. 7. The relative size of the two ions plays a role in determining the ___________________ of the ________________________ as they pack together. 8. The fact that the ions in an ionic solid are held in fixed positions by their attractive forces make the ionic solid ______________________________ and ______________________________. This also enables them to be good _______________________________ of electricity and have ____________________ melting points. 9. In order to conduct electricity, an ionic solid must be dissolved or in the _______________________ state so that __________________ ____________________ ions are present. 8 What Kind Of Bond Am I? Unlike Thomas Jefferson’s view of people, all atoms are not created equal. We have already seen that there are complex patterns to the trends in ionization energy, electron affinity and electronegativity that describe an atom’s ability to gain, lose or attract electrons. We know that it is easier to remove an electron from K than it is from Li, but we’ve not considered how these various atomic effects might affect bonding between atoms. A chemical bond is a linkage of atoms by transferring or sharing valence electrons, those outermost _______ and _______ electrons. But why do atoms bond together? We can answer that by looking at the group of atoms that do not bond — ________________________. The reason they are so stable is their outer s and p orbitals are filled, the same electron configurations that other atoms strive to achieve. This can occur by rearranging the outer electrons between two atoms. From the definition, we can see that there are two general types of bonds in compounds, those that result from electron _________________ and the second class that results from electron _______________. When electrons transfer from one atom to another, positive and negative ions are formed that are held together by an electrostatic attraction. This is called an ionic bond and is usually formed between a _________________________ and a _________________________. EXAMPLE: NaCl ----> the Na atom has _____ valence electron; Cl atom has _____ valence electrons.