The Periodic Table Preview Understanding Concepts Reading Skills Interpreting Graphics

Understanding Concepts 1. What group of elements is the least reactive? A. halogens B. alkali metals C. noble gases D. semiconductors

Understanding Concepts 1. What group of elements is the least reactive? A. halogens B. alkali metals C. noble gases D. semiconductors

Understanding Concepts, continued 2. What does the symbol Li+ represent? F. a lithium isotope G. a lithium atom H. a lithium ion I. a lithium molecule

Understanding Concepts, continued 2. What does the symbol Li+ represent? F. a lithium isotope G. a lithium atom H. a lithium ion I. a lithium molecule

Understanding Concepts, continued 3. What information about an element is most crucial for locating that element in the periodic table? A. the element’s atomic number B. the element’s electric charge C. the element’s most common isotope D. the number of orbitals the element has

Understanding Concepts, continued 3. What information about an element is most crucial for locating that element in the periodic table? A. the element’s atomic number B. the element’s electric charge C. the element’s most common isotope D. the number of orbitals the element has

Understanding Concepts, continued 4. Carbon, whose atomic number is 6, has four valence electrons. Sulfur’s atomic number is 16, and sulfur is located two columns to the right of carbon and one row down on the periodic table. How many valence electrons does sulfur have? F. 4 H. 7 G. 6 I. 14

Understanding Concepts, continued 4. Carbon, whose atomic number is 6, has four valence electrons. Sulfur’s atomic number is 16, and sulfur is located two columns to the right of carbon and one row down on the periodic table. How many valence electrons does sulfur have? F. 4 H. 7 G. 6 I. 14

Understanding Concepts, continued 5. Why are the elements in Group 1 the most reactive?

Understanding Concepts, continued Why are the elements in Group 1 the most reactive? Answer: They have only one valence electron, which is easily shared with any element with a partially filled electron orbital.

Understanding Concepts, continued If the element ununoctium is ever synthesized,it will be located directly under radon, xenon and krypton on the periodic table. What would ununoctium’s atomic number be? Predict ununoctium’s properties.

Understanding Concepts, continued If the element ununoctium is ever synthesized,it will be located directly under radon, xenon and krypton on the periodic table. What would ununoctium’s atomic number be? Predict ununoctium’s properties. Answer: 118; inert, nonreactive, full electron shells

Understanding Concepts, continued 7. What group of elements has some properties of metals and some properties of nonmetals? How does the periodic table reflect this fact?

Understanding Concepts, continued What group of elements has some properties of metals and some properties of nonmetals? How does the periodic table reflect this fact? Answer: Metalloids, or semiconductors; they are located on the border between the metals and nonmetals.

MENDELEEV’S DISCOVERY Reading Skills MENDELEEV’S DISCOVERY On March 6, 1869, Mendeleev made a formal presentation to introduce his new periodic table. He explained that elements that have similar chemical properties either have atomic masses that are nearly the same value (as have Os, Ir and Pt) or have atomic masses that increase regularly (as have K, Rb, and Cs). Arranging the elements in rows, within which they are in order of their atomic masses, creates columns corresponding to electron valencies. The elements whose particles are the most widely diffused—gases—have small atomic masses. Mendeleev told scientists that they should expect the discovery of some new elements. Two of the elements whose existence he predicted are gallium and germanium. Based on their location in the periodic table (directly below aluminum and silicon), he accurately predicted their atomic masses to be between 65 and 75.

Reading Skills, continued Based on the passage, what does the word diffused mean? A. close together B. spread apart C. a high temperature D. a low temperature

Reading Skills, continued Based on the passage, what does the word diffused mean? A. close together B. spread apart C. a high temperature D. a low temperature

Reading Skills, continued What is one of the widely diffused elements Mendeleev was likely referring to in his presentation? F. bromine G. iodine H. helium I. uranium

Reading Skills, continued What is one of the widely diffused elements Mendeleev was likely referring to in his presentation? F. bromine G. iodine H. helium I. uranium

Reading Skills, continued 10. When Mendeleev predicted the existence of the elements gallium and germanium, he temporarily named these elements ekaaluminum and ekasilicon. What does the prefix eka- mean, in terms of the layout of the periodic table?

Reading Skills, continued 10. When Mendeleev predicted the existence of the elements gallium and germanium, he temporarily named these elements ekaaluminum and ekasilicon. What does the prefix eka- mean, in terms of the layout of the periodic table? Answer: In the same column, because of similar properties; but one row down, because of a higher atomic number.

Interpreting Graphics The graphic below shows the bonding of sodium and chlorine to form sodium chloride, NaCl. Use this graphic to answer questions 11 and 12.

Interpreting Graphics, continued 11. How many total valence electrons do the two atoms have? A. 0 C. 7 B. 1 D. 8

Interpreting Graphics, continued 11. How many total valence electrons do the two atoms have? A. 0 C. 7 B. 1 D. 8

Interpreting Graphics, continued 12. What is the mass of one mole of NaCl molecules? F. 28 g H. 1.68 × 1025 g G. 58 g I. 3.49 × 1025 g

Interpreting Graphics, continued 12. What is the mass of one mole of NaCl molecules? F. 28 g H. 1.68 × 1025 g G. 58 g I. 3.49 × 1025 g

Interpreting Graphics, continued The graphic below shows the upper right segment of the periodic table. Use this graphic to answer questions 13–15.

Interpreting Graphics, continued 13. Which pair of elements would most likely have a similar arrangement of outer electrons and have similar chemical behaviors? A. boron and aluminum C. carbon and nitrogen B. helium and fluorine D. chlorine and oxygen

Interpreting Graphics, continued 13. Which pair of elements would most likely have a similar arrangement of outer electrons and have similar chemical behaviors? A. boron and aluminum C. carbon and nitrogen B. helium and fluorine D. chlorine and oxygen

Interpreting Graphics, continued 14. What is the atomic mass of helium?

Interpreting Graphics, continued What is the atomic mass of helium? Answer: 4.00 u

Interpreting Graphics, continued 15. How many neutrons does the average helium atom contain?

Interpreting Graphics, continued How many neutrons does the average helium atom contain? Answer: 2