A1: Atomic Structure Worksheet (Goals 1 3, Chapter 4)

Transcription

1 Unit 3 Assignment Packet Name: Period: A1: Atomic Structure Worksheet (Goals 1 3, Chapter 4) 1. Democritus, who lived in Greece during the 4 th century B.C., suggested that is made up of tiny particles that cannot be divided. He called these particles. 2. Explain why the ideas of Democritus were not useful in a scientific sense. 3. The modern process of discovery about atoms began with the theories of an English school teacher named. 4. Circle the letter of each sentence that is true about Dalton s atomic theory. a. All elements are composed of tiny, indivisible particles called atoms. b. An element is composed of several types of atoms. c. Atoms of different elements can physically mix together, or can chemically combine in simple whole number ratios to form compounds. d. Chemical reactions occur when atoms are separated, joined, or rearranged; however, atoms of one element are never changed into atoms of another element when the atoms of elements A and B combine chemically. 5. Which atomic particles carry a negative charge? 6. Thomson observed that the production of cathode rays did not depend on the kind of gas in the tube or the type of metal used in the electrodes. What conclusion did he draw from these observations? 7. Explain Thomson s Plum Pudding model of the atom (often called the cookie dough model). 8. How many units of positive charge remain if a hydrogen atom loses an electron? 9. The positively charged subatomic particle that remains when a hydrogen atom loses an electron is called a(n). 10. Circle the letter of each sentence that is true about the nuclear theory of atoms suggested by Rutherford s experimental results. a. An atom is mostly empty space. b. All the positive charge of an atom is concentrated in a small central region called the nucleus. c. The nucleus is composed of protons. d. The nucleus is large compared with the atom as a whole. e. Nearly all the mass of an atom is in its nucleus.

2 11. Describe Rutherford s gold foil experiment and explain how his results improved upon Thomson s Plum Pudding model of the atom. 12. Fill out the following table: Name Symbol Charge Mass (amu) electron proton neutron 13. Would you expect two electrons to attract or repel each other? Why? 14. What is the charge, positive or negative, of the nucleus of every atom? 15. Why is every atom electrically neutral? A2: Isotopes Worksheet (Goal 4 5, Chapter 4) 1. Write the isotopic symbols for the isotopes of uranium having the following number of neutrons. a. 142 neutrons b. 143 neutrons c. 146 neutrons 2. Fill in the following table: Name # of protons # of neutrons # of electrons Boron-10 Sulfur- 17 Iodine Calcium What do isotopes of the same element have in common? How do isotopes of the same element differ?

3 4. Fill in the following table: Name # of electrons # of protons # of neutrons atomic number mass number carbon tin Write the isotopic symbols for argon-36, argon-38, and argon How can there be more than 1000 different atoms when there are only about 100 different elements? 7. How is the carbon-12 atom used to define atomic mass unit? 8. Distinguish among atomic mass and mass number. 9. What data must you know about the isotopes of an element to calculate the atomic mass of the element? 10. Element X has two naturally occurring isotopes. The isotope with mass of 10.0 amu has a relative abundance of 20.0%. The isotope with a mass of 11.0 amu has a relative abundance of 80.0%. Calculate the value of the atomic mass of element X. State the atomic number and true identity of element X.

4 11. The lithium found in a hearing aid battery has two naturally occurring isotopes. Lithium-6 has a mass of 6.01 amu and an abundance of 7.42%. Lithium-7 has a mass of 7.01 amu and an abundance of 92.58%. Calculate the atomic mass of lithium. 12. Bohr Model Practice Problems Directions: complete each of the following models using what you know about atoms. The first is completed for you as an example. Atomic # 7 Atomic Mass 14 Atomic Mass_12_ Atomic Mass_40_ Atomic Mass Element: Nitrogen Symbol_ N_ Symbol C_ Symbol Symbol _H_ Atomic Mass_40_ Atomic Mass_11_ Atomic Mass_27_ Atomic Mass_32_ Symbol Symbol _B_ Symbol Element: Symbol A3: Atomic Theory and Orbitals Worksheet (Goals 6-9, Chapter 5) 1. Describe how the quantum theory of atomic structure differs from Bohr s theory. ( Hint: Focus on electrons) 2. Differentiate between an orbit and an orbital.

5 3. How are electrons in the ground state different from electrons in the excited state? 4. What unusual property is observed when an electron falls from excited state to a ground state? 5. How many orbitals are in the fourth energy level? 6. How many orbitals of each type are there? s- p- d- f- 7. Draw pictures of a single 2s and 2p orbital. 8. What is a line spectrum? What does it represent? 9. Fireworks give off many different colors. Using Bohr s theory and your observations from the spectroscope, explain how the firework s chemicals produce different colors. 10. Why do we not see a line spectrum with our eyes from the fireworks? Atomic Orbitals and the Periodic Table 1s 2s 2p 3s 3p 3d 4s 4p 4d 4f 5s 5p 5d 5f 6s 6p 6d 7s 7p 7d

6 Rule 1: Aufbau Principle: electrons enter orbitals of lowest energy first Rule 2: Hund's Rule: when electrons occupy orbitals of equal energy, one electron enters each orbital until all of the orbitals contain one electron with parallel spins Rule 3: Pauli Exclusion Principle: an atomic orbital can describe at most two electrons Directions: Write complete Electron Configurations and Orbital Diagrams for the following. H Be C Ne Na Cl Fe Hg O 2- Ca 2+ A4: Electron configs w/ Shorthand (goals 6-9, Chaper 5) Rule 4: Noble Gas Shorthand Method: The last noble gas that was completed prior to arriving at your element can be written down with the symbol of that noble gas in [brackets]. Then complete the valence electrons to arrive at your element. We assume that the electrons are full in every shell up to that noble gas. Directions: Write complete Electron Configurations for the following empty boxes only. Noble Gas Element Long Method Shortcut Method Br 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 5 [Ar] 4s 2 3d 10 4p 5

7 Br -1 Mg He xxxxxxxxxxxxxx Li Element B Long Method Noble Gas Shortcut Method H xxxxxxxxxxxxxx S S -2 Ti As xxxxxxxxxxxxxx Na P xxxxxxxxxxxxxx Cr Co Ag Al xxxxxxxxxxxxxx Al +3 Ne xxxxxxxxxxxxxx

8 A6: The Periodic Table: Organizing the Elements (Goals 10-12, Chapter 6) A. periodic table B. metals C. nonmetals D. periods E. alkali metals F. halogens G. columns H. periodic law I. alkaline earth metals J. noble gases K. group L. transition metals M. metalloids N. inner transition metals O. atomic number P. representative elements Use this completion exercise to check your understanding of the concepts and terms associated with the organization of the periodic table. Each blank can be completed with a term. Some terms may be used more than once or not at all. Put the LETTER of the correct term in the space provided. The periodic table organizes the elements into vertical and horizontal in order of increasing. The table is constructed so that the elements having similar properties are in the same. The elements in Groups 1A through 7A are called the. The makeup Group 8A. The elements in Groups 2A and 3A are interrupted in periods 4 and 5 by the and in the periods 6 and 7 by the. The group 1A elements are called the, and the group 2A elements are called the. The nonmetals of group 7A are called the. Elements with properties that are intermediate between those of metals and nonmetals are called. Classify each statement as true or false. 1. In his periodic table, Mendeleev arranged elements in ascending order of atomic number The representative elements are the Group A elements. The transition metals and inner transition metals are the Group B elements. The element in group 4A, period 3, is gallium Match each description in Column B to the correct term in Column A. Column A Column B 5. periodic table a. A vertical column of elements in the 6. periods periodic table b. The Group 8A elements 7. group c. The Group 1A elements d. A portion of the Group B elements 8. representative elements 9. alkali metals 10. transition metals e. An arrangement of elements according to similarities in their properties f. Group A elements g. The horizontal rows of the periodic table h. The Group 7A element 11. halogens 12. noble gases

9 Answer the following questions in the space provided. 13. List the elements of Group 5A. Tell whether each is a metal, nonmetal, or metalloid. 14. List three properties of metals, nonmetals, and metalloids. A7: Periodic Table and Trends (Goals 10-12, Chapter 6) 1. What determines the vertical arrangement of the periodic table? 2. What determines the horizontal order of the periodic table? 3. What determines the order of the periodic table? 4. Why did Mendeleev and other scientists of his time arrange elements in the periodic table in order of atomic masses? 5. All halogens are highly reactive. What causes the similarity among the halogens? 6. What properties do Noble gasses share and how does this relate to their electron configuration? 7. For each element tell which period and group the element is in, identify the element, and state whether it is a metal, nonmetal, or metalloid. Element Period Group Identity Metal, non, metalloid #34 #40 #14 #56 #18

10 8. Classify the following as metals, nonmetals or metalloids below each name: manganese. arsenic carbon niobium radium 9. Iodine is used in many commercial chemicals and dyes. To what family does it belong? What are the other members of this family? How many electrons are in the outermost energy level? 10. Define atomic size and describe its trend on the periodic table. 11. Define ionization energy and describe its trend on the periodic table. 12. Define electronegativity and describe its trend on the periodic table. 13. Explain why as you go down the periodic table, within a group, the atoms get larger. 14. Explain why as you go across the periodic table to the right, within a period, the atoms get smaller. 15. As an atom gets smaller the ionization energy becomes greater. Using atomic structure, explain this statement. 16. Explain how electronegativity is related to atomic size using the trends on the periodic table.