Ionic Bonds SE

Name: Date: 09/16/202 Student Exploration: Ionic Bonds Directions: Follow the instructions to go through the simulation. Respond to the questions and prompts in the orange boxes. Vocabulary: chemical family, ion, ionic bond, ionization energy, metal, nonmetal, octet rule, shell, valence electron Prior Knowledge Questions (Do these BEFORE using the Gizmo.) Nate and Clara are drawing pictures with markers. There are 8 markers in a set. Nate has 9 markers and Clara has 7. What can Nate and Clara do so that each of them has a full set? Nate had to give one marker to Clara. Maggie is sitting at a table with Fred and Florence. Maggie has 10 markers, but Fred and Florence each have only 7 markers. How can they share markers so each has 8? Maggie had to give one marker to Fred and one to Florence. Gizmo Warm-up Just like students sharing markers, atoms sometimes share or swap electrons. By doing this, atoms form bonds. The Ionic Bonds Gizmo allows you to explore how ionic bonds form. To begin, check that Sodium (Na) and Chlorine (Cl) are selected from the menus at right. Click Play ( ) to see electrons orbiting the nucleus of each atom. (Note: These atom models are simplified and not meant to be realistic.) Each atom consists of a central nucleus and several shells that contain electrons. The outermost electro ns are called valence electrons . How many valence electrons does each atom have? Sodium: 1 Chlorine: Click Pause ( ). Elements can be classified as metals and nonmetals . Metals do not hold on to their valence electrons very tightly, while nonmetals hold their electrons tightly. Ionization energy is a measure of how tightly the valence electrons are held. Try pulling an electron away from each atom. Based on this experim 7 ent, which atom is a metal? Sodium, Na Which is a nonmetal? Chlorine, Cl Try moving an electron from the metal to the nonmetal. What happens? They make a bond because of the sharing(or transferring) of one electron. Get the Gizmo ready: Click Activity A: Reset . Ions Check that sodium and chlorine are still selected. Introduction: Some of the particles that make up atoms have an electrical charge. Electrons are negatively charged, while protons are positively charged. Particles with opposite charges (+ and –) attract, while particles with the same charge (+ and + or – and –) repel. Question: What happens when atoms gain or lose electrons? Count : Electrons move around the nucleus of atoms in specif ic shells, shown by the rings around the atoms in the Gizmo. The first ring holds two electrons, and the second holds eight. (If you like, you can hide the inner electrons by selecting Hide inner electrons .) Observe the sodium and chlorine atoms. How many electrons are there total in each atom? Sodium: 11 Chlorine: 17 Each atom is neutrally charged, which means that each atom has the same number of protons and electrons. Based on this, how many protons are in each atom? Sodium: 11 Chlorine: 17 Observe : Most atoms are stable with a configuration of eight valence electrons. This is known as the octet rule . How many valence electrons does each atom have? Sodium: lose 1 electrong Chlorine: It has 7 but it gains 1 Form a bond : Each electron has a charge of 1–, and each proton has a charge of 1+. You can calculate the charge of an atom by subtracting the number of electrons from the number of protons. Move an electron from the sodium to the chlorine atom. A. What are the charges of each atom now? Sodium: 1+ Chlorine: 1- B. Is each ion stable? Explain. Yes, because the sodium loses one electron so it becomes stable and chlorine gains one so it becomes stable too. And their valence shell become full. Think and discuss : Why is there an attraction between the two ions in this chemical bond? Because the sodium gives one electron to the chlorine so they make a bond. Get the Gizmo ready: Click Reset . Turn off Activity B: Show charge . Ionic compounds Select Lithium (Li) and Oxygen (O) . Question: How are ionic compounds formed? Observe : Look at the purple lithium atom and the red oxygen atom. Recall that most atoms are stable when their outermost ring has eight electrons. Some atoms, such as lithium and beryllium, are stable when their outermost ring has two electrons. A. How many electrons will the lithium atom give up to become stable? B. How many electrons does the oxygen atom need to become stable? Lithium loses 1 electron. Oxygen needs to gain 2 electrons. C. Can a stable compound be made from these two atoms? Explain why or why not. Yes, because Oxygen gains two electrons and Lithium is metal that loses 1 electrons. Form bonds : Click Add metal to add another lithium atom, and then transfer electrons from the lithium to the oxygen. Click Check . A. Did you make a stable compound? B. Turn on Show formula. What is the formula of this compound? Yes Li2O C. Turn on Show charge. What is the charge of each ion? Li 1+ Li 1+ O 2- Practice : Use the Gizmo to create stable compounds from the combinations given below. After transferring electrons, arrange the atoms to demonstrate the attraction between positively charged ions and negatively charged ions. Click Check to check each compound. Ionic charges Chemical formula A. Lithium and fluorine: Li 1+ B. Beryllium and oxygen: Be 2+ O C. Magnesium and fluorine: Mg 2+ F D. Aluminum and chlorine: Al E. Beryllium and nitrogen Be F 3+ 2+ Cl N 3- 1- LiF 2- BeO 1- MgF2 1- AlCl3 Be3N2 Get the Gizmo ready: Select Extension: Lithium (Li) from the Chemical families Select a metal list. You will need a periodic table for this activity. Introduction: The periodic table arranges elements by size and property. The vertical columns represent chemical families, or groups of elements with similar chemical properties. Question: How are elements arranged into chemical families? Observe : Drag the nonmetal into the trash ( ) so there is only one lithium atom visible. A. How many valence electrons does lithium have? 1 B Now look at your periodic table. Find lithium (Li) in the first column. Other than lithium, which element from the Gizmo is also in this column? Na C. Choose this element. How many valence electrons does this element have? 1 Gather data : Four other pairs of elements in the same chemical family are listed below. List the number of valence electrons in each element. Beryllium 2 Nitrogen 5 Oxygen 6 Fluorine 7 Magnesium 2 Phosphorus 5 Sulfur 6 Chlorine 7 Analyze : What pattern do you see? In every column all elements have the same valence shell electrons number. Make a rule : Based on your data, how are elements arranged into chemical families? Based by their number of electrons in valence shell. 5. Infer: Look at your periodic table. How many valence electrons would you find for elements in each family? Boron family: 3 Carbon family: 4 Neon family: 8 6. Think and discuss: How do you think the number of valence electrons relates to an element’s chemical properties? because sharing electrons between atoms makes bonds and that bond has very important rules in chemical properties.