Organizing the Elements

Organizing the Elements 6.1 • In a self-service store, the products are grouped according to similar characteristics. With a logical classification system, finding and comparing products is easy. You will learn how elements are arranged in the periodic table and what that arrangement reveals about the elements.

6.1 Searching For an Organizing Principle • Searching For an Organizing Principle • How did chemists begin to organize the known elements?

6.1 Searching For an Organizing Principle • Chemists used the properties of elements to sort them into groups.

6.1 Searching For an Organizing Principle • Chlorine, bromine, and iodine have very similar chemical properties.

6.1 Mendeleev’s Periodic Table • Mendeleev’s Periodic Table • How did Mendeleev organize his periodic table?

6.1 Mendeleev’s Periodic Table • Mendeleev arranged the elements in his periodic table in order of increasing atomic mass. • The periodic table can be used to predict the properties of undiscovered elements.

6.1 Mendeleev’s Periodic Table • An Early Version of Mendeleev’s Periodic Table

6.1 The Periodic Law • The Periodic Law • How is the modern periodic table organized?

6.1 The Periodic Law • In the modern periodic table, elements are arranged in order of increasing atomic number.

6.1 The Periodic Law • The periodic law: When elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties. • The properties of the elements within a period change as you move across a period from left to right. • The pattern of properties within a period repeats as you move from one period to the next.

6.1 Metals, Nonmetals, and Metalloids • Metals, Nonmetals, and Metalloids • What are three broad classes of elements?

6.1 Metals, Nonmetals, and Metalloids • Three classes of elements are metals, nonmetals, and metalloids. • Across a period, the properties of elements become less metallic and more nonmetallic.

6.1 Metals, Nonmetals, and Metalloids • Metals, Metalloids, and Nonmetals in the Periodic Table

6.1 Metals, Nonmetals, and Metalloids • Metals • Metals are good conductors of heat and electric current. • 80% of elements are metals. • Metals have a high luster, are ductile, and are malleable. • Have only a few electrons in their outer shell

6.1 Metals, Nonmetals, and Metalloids • Uses of Iron, Copper, and Aluminum

6.1 Metals, Nonmetals, and Metalloids • Nonmetals • In general, nonmetals are poor conductors of heat and electric current. • Most nonmetals are gases at room temperature. • A few nonmetals are solids, such as sulfur and phosphorus. • One nonmetal, bromine, is a dark-red liquid. • Usually have more than 3 electrons in their outer shell.

6.1 Metals, Nonmetals, and Metalloids • Metalloids • A metalloid generally has properties that are similar to those of metals and nonmetals. • The behavior of a metalloid can be controlled by changing conditions.

6.1 Metals, Nonmetals, and Metalloids • If a small amount of boron is mixed with silicon, the mixture is a good conductor of electric current. Silicon can be cut into wafers, and used to make computer chips.

6.1 Section Quiz • 1. The modern periodic table has elements arranged in order of • colors. • melting and boiling points. • increasing atomic mass. • increasing atomic number.

6.1 Section Quiz • 2. Mendeleev arranged the elements in his periodic table in order of increasing • atomic number. • number of protons. • number of electrons. • atomic mass

6.1 Section Quiz • 3. Which one of the following is NOT a general property of metals? • ductility • malleability • having a high luster • poor conductor of heat and electricity

6.2 Squares in the Periodic Table • Squares in the Periodic Table • What type of information can be displayed in a periodic table?

6.2 Squares in the Periodic Table • The periodic table displays the symbols and names of the elements, along with information about the structure of their atoms.

6.2 Squares in the Periodic Table • The background colors in the squares are used to distinguish groups of elements. • The Group 1A elements are called alkali metals. • The Group 2A elements are called alkaline earth metals. • Group 6A elements are called the chalcogens. • The nonmetals of Group 7A are called halogens.

6.2 Squares in the Periodic Table

6.2 Electron Configurations in Groups • Electron Configurations in Groups • How can elements be classified based on their electron configurations?

6.2 Electron Configurations in Groups • Elements can be sorted into noble gases, representative elements, transition metals, or inner transition metals based on their electron configurations.

6.2 Electron Configurations in Groups • The blimp contains helium, one of the noble gases.

6.2 Electron Configurations in Groups • The Noble Gases • The noble gases are the elements in Group 8A of the periodic table. The electron configurations for the first four noble gases in Group 8A are listed below.

6.2 Electron Configurations in Groups • The Representative Elements • Elements in groups 1A through 7A are often referred to as representative elements because they display a wide range of physical and chemical properties. • The s and p sublevels of the highest occupied energy level are not filled. • The group number equals the number of electrons in the highest occupied energy level.

6.2 Electron Configurations in Groups • In atoms of the Group 1A elements below, there is only one electron in the highest occupied energy level.

6.2 Electron Configurations in Groups • In atoms of the Group 4A elements below, there are four electrons in the highest occupied energy level.

6.2 Representative Elements • Representative Elements

6.2 Transition Elements • Transition Elements • There are two types of transition elements—transition metals and inner transition metals. They are classified based on their electron configurations.

6.2 Transition Elements • In atoms of a transition metal, the highest occupied s sublevel and a nearby d sublevel contain electrons. • In atoms of an inner transition metal, the highest occupied s sublevel and a nearby f sublevel generally contain electrons.

6.2 Transition Elements • Blocks of Elements

6.2 Section Quiz • 1. Which of the following information about elements is usually NOT included in a periodic table? • color • symbol • atomic number • atomic mass

6.2 Section Quiz • 2. An alkali metal would have in the highest occupied energy level • an s2 electron. • an s1 electron. • p2electrons. • p6 electrons.

6.2 Section Quiz • 3. Which one of the following is incorrectly labeled? • Ne, noble gas • Cu, transition metal • Ga, transition metal • Cl, halogen

6.2 Section Quiz • 4. Transition metals are characterized as being different than representative elements because they have electrons in which suborbitals? • p • d • s • f

6.3 Periodic Trends • Sodium chloride (table salt) produced the geometric pattern in the photograph. Such a pattern can be used to calculate the position of nuclei in a solid. You will learn how properties such as atomic size are related to the location of elements in the periodic table.

6.3 Trends in Atomic Size • Trends in Atomic Size • What are the trends among the elements for atomic size?

Organizing the Elements