Name:_______________________________ Assignment #:_______ Investigating the Periodic Table 6.1 & 6.2 Worksheet In examining the modern periodic table, one notices the chemical elements arranged in groups and periods. They are classified by their general physical and chemical properties into their groups: metal, metalloids, and nonmetals, which can be further subdivided. These classifications help chemists understand the known elements and predict the properties of new manmade elements. Let’s investigate some of these properties more closely. 1. Use the chart to color in your periodic table and complete the “Group Number” column. Color Atomic Numbers Family Name Blue 3, 11, 19, 37, 55, 87 Alkali Metals Red 4, 12, 20, 38, 56, 88 Alkaline Earth Metals Yellow 21-30, 39-48, 72-80, 104-109 Transition Metals Pink 13, 31, 49, 50, 81, 82, 83 Other Metals Purple 5, 14, 32, 33, 51, 52, 84 Metalloids Green 1, 6, 7, 8, 15, 16, 34 Non-Metals Brown 9, 17, 35, 53, 85 Halogens Gray 2, 10, 18, 36, 54, 86 Noble Gases Orange 57-71, 89-103 Inner Transition Elements Group Number(s) 2. What do you notice about the elements within a given group? Within a period? 3. The electron configuration of an atom reveals the placement of electrons within the orbitals of the atom and is a key to chemical behavior. However, it is mostly the outer-shell (or valence) electrons that will be engaged in bonding and reactivity. We can write a shorthand electron configuration that helps to highlight these electrons through “the noble gas method.” In this shorthand, write the last noble gas configuration the element achieved in brackets and then write the electrons that were added after that. Examples: Sodium is [Ne]3s1 and Bromine is [Ar]4s23d104p5 Write shorthand electron configurations for the following atoms: o Lithium o Sodium o Potassium What do these electron configurations have in common? What would you expect about the relative properties of these elements? What group are these elements located in? How does their position on the periodic table compare to their electron configuration? Name:_______________________________ Assignment #:_______ Write shorthand electron configurations for the following atoms: o Fluorine o Chlorine o Bromine What do these electron configurations have in common? What would you expect about the relative properties of these elements? What group are these elements located in? How does their position on the periodic table compare to their electron configuration? 4. Atoms become electrically charged by gaining or losing electrons. The typical number of electrons gained or lost is related to electron configuration and to position in the periodic table. The goal of an atom in forming an ion is to become isoelectronic to a noble gas. That means the ion form is trying to achieve the stable octet (s2p6) outer-shell configuration of a noble gas. Calcium, element 20, tends to form a 2+ ion, this means it has lost two electrons (remember, we can’t add protons). Write the electron configuration of a Ca atom and of a Ca2+ ion. o Ca o Ca2+ Explain why the 2+ ion is the one that tends typically to form In what group of the periodic table is Ca located? What ions would the other elements in this group tend to form? Why do you think that? Sulfur, element 16, tends to form a 2- ion, this means it has gained two electrons (remember, we can’t lose protons). Write the electron configuration of a sulfur atom and of a S2- ion. o S o S2 Explain why the 2- ion is the one that tends typically to form In what group of the periodic table is S located? What ions would the other elements in this group tend to form? Why do you think that? Name:_______________________________ Assignment #:_______ 5. Putting the concepts together: Looking at the periodic table, predict the valance number (number of electrons in the highest occupied energy level) and possible ion charge of the various groups on the periodic table. Group 1 Group 2 Group 13 Group 14 Group 15 Group 16 Group 17 Outershell Configuration Valence Number Ion Charge 6. Circle the correct response that would make each statement true: a. Metals would tend to (lose/gain) electrons to form (positive/negative) ions. b. Nonmetals would tend to (lose/gain) electrons to form (positive/negative) ions. 7. How did Mendeleev organize the periodic table? How did Moseley organize the periodic table? 8. Identify the following elements based on the clues provided: a. [Ar] 4s23d8 b. A metal in Group 15 c. An element with 5 electrons in the third energy level d. The halogen found in a liquid state at room temperature e. Group 14 element in Period 4 f. The transition metal with the smallest atomic mass g. The alkali earth metal with the largest atomic number h. The element in Period 4, Group 17 Group 18 Name:_______________________________ Assignment #:_______ Other things to know about the various families: Alkali Metals The alkali metals are very reactive metals that do not occur freely in nature. As with all metals, the alkali metals are malleable, ductile, and are good conductors of heat and electricity. The alkali metals are softer than most other metals. Cesium and francium are the most reactive elements in this group. Alkali metals can explode if they are exposed to water and are stored under oil. The alkali metals have an oxidation number of +1. Alkaline Earth Metals The alkaline earth elements are metallic elements found in the second group of the periodic table. All alkaline earth elements have an oxidation number of +2, making them very reactive. Because of their reactivity, the alkaline metals are not found free in nature. Transition Metals The elements in groups 3 through 12 of the periodic table are called "transition metals" (previously called heavy metals). As with all metals, the transition elements are both ductile and malleable, and conduct electricity and heat. The interesting thing about transition metals is that their valence electrons, or the electrons they use to combine with other elements, are present in more than one shell, so their common ion charge cannot be predicted solely by their position on the periodic table. Other Metals The 7 elements classified as "other metals" are located in groups 13, 14, and 15. While these elements are ductile and malleable, they are not the same as the transition elements. These elements, unlike the transition elements, do not exhibit variable oxidation states, and their valence electrons are only present in their outer shell. All of these elements are solid, have a relatively high density, and are opaque. Metalloids Metalloids are the elements found along the stair-step line that distinguishes metals from non-metals. This line is drawn from between Boron and Aluminum to the border between Polonium and Astatine. The only exception to this is Aluminum, which is classified under "Other Metals". Metalloids have properties of both metals and non-metals. Some of the metalloids, such as silicon and germanium, are semi-conductors. This means that they can carry an electrical charge under special conditions. Non-metals Non-metals are the elements in groups 14-16 of the periodic table. Non-metals are not able to conduct electricity or heat very well. As opposed to metals, non-metallic elements are very brittle, and cannot be rolled into wires or pounded into sheets. The non-metals exist in two of the three states of matter at room temperature: gases (such as oxygen) and solids (such as carbon). The non-metals have no metallic luster, and do not reflect light. Halogens The halogens are five non-metallic elements found in group 7 of the periodic table. The term "halogen" means "saltformer" and compounds containing halogens are called "salts". All halogens have 7 electrons in their outer shells, giving them an oxidation number of -1. The halogens exist, at room temperature, in all three states of matter: SolidIodine, Astatine; Liquid- Bromine; Gas- Fluorine, Chlorine. Noble Gases The six noble gases are found in group 18 of the periodic table. These elements were considered to be inert gases until the 1960's, because their oxidation number of 0 (they don’t gain or lost electrons) prevents the noble gases from forming compounds readily. All noble gases have the maximum number of electrons possible in their outer shell (2 for Helium, 8 for all others), making them stable. Inner Transition Elements The inner transition elements are composed of the lanthanide and actinide series. They used to be called the rare earth metals because they are difficult to find, not necessarily because they are rare. The lanthanides are so similar in chemical and physical properties that they are difficult to separate from each other. The actinides are all unstable, and most do not occur in nature.