Survey
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Name____________________ Date Period Understanding the Atom 3.1 Discovering Parts of an Atom Directions: On the line before each statement, write correct if the statement is correct or not correct if the statement is not correct. If the statement is not correct, change the underlined word(s) to make it correct. (30 points this side) _______ 1. Early Greek philosophers, such as Democritus, thought that all matter was made of fire, water, air, and earth. _______ 2. John Dalton’s atomic theory supported some of the ideas of Aristotle. _______ 3. An atom is the smallest piece of an element that still represents the element. _______ 4. Atoms are so small that about 7.5 million carbon atoms could fit into the period at the end of this sentence. _______ _______ 5. An electron is a particle with one negative charge. _______ 7. Niels Bohr discovered the existence of neutrons, or neutral particles, in the nucleus of an atom. _______ 8. According to the modern atomic model, electrons form an electron cloud around the nucleus. _______ 9. Modern scientists believe that protons and neutrons are not made of smaller particles. 6. Rutherford’s atomic theory stated that most of an atom’s mass is concentrated in the nucleus. Matching Directions: On the line before each definition, write the letter of the term that matches it correctly. Not all terms are used. Write the terms NOT USED and a definition. A. nucleus 1. particle with one negative charge 2. smallest particle of an element that still represents that element 3. particle with one positive charge 4. neutral particle found in the nucleus B. C. D. E. F. electron neutron proton quark atom Directions: Label this diagram by writing the correct term from the word bank on each line. electron cloud neutron nucleus proton Directions: Answer each question. 10. Is it possible to see atoms with your eyes? Explain. 11. What is an STM? 12. How have STMs helped scientists study atoms? 1 Utah Core Curriculum Standard I Davis School District Buffalo Book Chapter 3 Online Physical Science Bubble Book Chapter 9 Name____________________ A. Early Ideas About Matter (40 points this side) 1. Many ancient Greek philosophers thought that all matter was made of only four elements—fire, water, air, and _______. 2. These early scientists were not able to ______ their theories. 3. Democritus proposed that matter is made of small, indivisible objects 4. He proposed that different types of ________________ are made from different types of atoms. B. Dalton’s Atomic Model 1. John Dalton proposed the _________ theory, which was based on careful observations and __________ of chemical reactions. 2. Dalton’s theory states that atoms cannot be divided, foil, but some bounced to the ____________, and a few bounced straight back. 3. Rutherford’s resulting atomic model proposed that most of an atom’s ____________ and ____________ charge is concentrated in ___________, or destroyed. It also stated that atoms of one ____________ are different from atoms of other ____________. a. The ________________ is the small, positively charged area in the center of the atom. b. In the nucleus is the ____________, which is an atomic particle with one positive charge. F. Discovering Neutrons 1. 2. 1. The atomic model of _______proposed that __________ move in circular orbits, or __________, around the nucleus. 2. When energy is added to an atom, electrons move to higher 1. A(n) _________ is the smallest piece of an element that still represents that element. 2. Atoms were first seen by using a(n) _________________ microscope. D. Thomson—Discovering Electrons 1. Thomson discovered that the rays in a(n) ____________ were ____________; when energy is released by the electron, it moves back to a lower level. 3. The limitation of Bohr’s model is that electrons do not actually move in orbits. H. The Modern Atomic Model attracted to a(n) ____________ charged plate, which means 1. In modern atomic theory, electrons form a(n) ___________, that the rays have a(n) ____________ charge. 2. Thomson’s atomic model stated that an atom is a positively charged which is an area around the ____________ in which an electron is likely to be located. ____________ with ____________ throughout it. E. Rutherford—Discovering the Nucleus 1. Rutherford’s student performed an experiment during which they shot ___________ particles into a piece of ___________ foil. Utah Core Curriculum Standard I ____________ was one of Rutherford’s colleagues. Chadwick discovered the ____________, a neutral particle that exists in the ____________ of an atom. G. Bohr’s Atomic Model C. The Atom 2 Date Period The results showed that most of the particles traveled through the the center of the atom. called ____________. 3. 2. I. 2. An electron cloud is mostly ____________ space. Quarks 1. Protons and ____________ are made of smaller parts called ____________. 2. There are ____________types of quarks. Davis School District Buffalo Book Chapter 3 Online Physical Science Bubble Book Chapter 9 (30 points this side) Name____________________ Date Period Directions: Complete the crossword puzzle with the correct terms from the word bank. Atomic Theory Magic Square Put the number of the definition from the list below on the line in the square with the appropriate term. Check your answers by adding the numbers in each row and column. They should add up to the same number. Democritus _____ Dalton _____ Thomson _____ element _____ Rutherford _____ proton _____ atom _____ Bohr _____ quark _____ neutron _____ nucleus _____ alpha particle _____ electron _____ Chadwick _____ energy levels _____ electron cloud _____ 1. current explanation of where electrons might be found in the atom 2. English schoolteacher who proposed the atomic theory model of matter 3. proposed the plum-pudding model of the atom; discovered the electron 4. the negative particle that circles the nucleus 5. developed the model of the atom in which electrons orbit the nucleus in energy levels 6. the neutral particle in the nucleus of an atom 7. the tiny positive core of an atom; contains protons and neutrons 8. discovered the nucleus using his gold foil experiment 9. small particles that make up protons and neutrons 10. the smallest particle of an element that has the properties of that element 11. the positive particle in the nucleus of an atom 12. used by Rutherford in his experiment; made of two protons and two neutrons 13. Greek philosopher who made a mental model of the atom 14. the paths in which electrons circle the nucleus according to the Bohr model 15. discovered the neutron 16. building blocks of matter represented by a symbol atoms electron electron cloud neutron nucleus proton Down 2. area around the nucleus where an electron is most likely to be 4. neutral particle that exists in the nucleus of an atom Across 6. smallest pieces of elements that still represent those elements 1. particle with one negative charge (1–) 3. small area in the center of an atom that contains most of the atom’s mass 5. particle with one positive charge (1+) 3 Utah Core Curriculum Standard I Davis School District Buffalo Book Chapter 3 Online Physical Science Bubble Book Chapter 9 (45 points this side) Name____________________ 3.2 Protons, Neutrons, and Electrons—How Atoms Differ A. The Parts of the Atom 1. ___________ and ___________ have about the same mass 2. ___________have much less mass than the other two particles in an atom. 3. Most of the mass of an atom is in the ___________. B. Different Elements—Different Numbers of Protons 1. The number of protons in an atom of an element is the element’s ___________. 2. Different elements contain different numbers of ___________. 3. In a neutral atom, the number of ___________ equals the number of protons because the number of __________charges must equal the number of positive charges. C. Neutrons and Isotopes ___________ are atoms of the same element that have different numbers of ___________. 2. The total number of ___________ and neutrons in an atom is the ___________of the atom. 3. The ___________ of an element is the average mass of the element’s ___________. a. The average atomic mass is ___________ according to the ___________of each atom in a sample and the number of atoms of that ___________that are present. D. Radioactivity 1. ______________first noticed that some elements spontaneously give off energy. 2. ______________________ called elements that Period 3. Radiation is made of energy and ___________ that come from the ___________ of radioactive atoms. 4. When atoms release particles of radiation, they change to different ___________. 5. _______________ ___________is a process that occurs when an unstable ___________ changes into another, more stable nucleus by emitting radiation. a. Nuclear decay can produce three different types of ___________. b. A(n) ___________ particle consists of___________ protons and two ___________. c. When alpha decay occurs, the atomic number of each atom that decays ___________ by ___________. d. 1. abundance of each isotope. b. Weighted means that the average atomic mass is based on the Date ___________ decay occurs when a neutron in an atom changes into a(n) ___________ and a high-energy electron called a(n) ___________ particle. e. When beta decay occurs, the atomic number of an atom___________ by ___________. f. Gamma rays contain a lot of ___________ but no particles.. g. ___________rays are sometimes emitted during nuclear decay, but this decay does not change one element into another element. 6. Energy released during radioactive decay can be either___________ or harmful. E. Ions—Gaining or Losing Electrons 1. A(n) ___________is an atom that is no longer neutral because it has gained or lost ___________. 2. A positive ion is an atom that has ___________ electrons. 3. A negative ion is an atom that has ___________ electrons. spontaneously emit radiation radioactive. 4 Utah Core Curriculum Standard I Davis School District Buffalo Book Chapter 3 Online Physical Science Bubble Book Chapter 9 Name____________________ Atomic Structure (42 points this column) Use Percentages _______________. The mass number of an atom is the sum of the number of ______________ and the 100 and then divide. For example, 25% equals The atomic number represents the number of _______________. 2. In a neutral atom the number of protons is always equal to the number of number of ______________. Use a copy of the periodic table in your planner and the information given in the data table to fill in the blanks. (1 point each blank square) Extra credit: draw and label any of the atoms. Substance Symbol Atomic Number Mass Number Number of Protons 2 4 Mg 12 Zinc 30 65 Bromine 80 Al 13 Uranium Sodium 11 Kr Calcium 40 20 Ag 47 Gold 79 197 Copper 64 Number of Neutrons Number of Electrons Helium 5 Period Percentages compare a partial amount to a whole amount, much like a fraction. The whole amount is equal to 100%. To change a percentage into a decimal, first write the percentage as a fraction with a denominator of 1. 3. Date 50 points this page Utah Core Curriculum Standard I A weighted average is a calculation based on the abundance, in percentages, of the items being averaged. Follow the steps below to calculate the weighted average atomic mass of an element. Copper (Cu) exists naturally in two isotopes. If copper is made up of 69.17% Cu-63 and 30.83% Cu-65, what is the average atomic mass of Cu? Step 1 Change each percentage to a decimal. 69.17% 12 25 , which is equal to 0.25. 100 = 0.617 100 30.83% = 0.3083 100 35 14 146 92 12 48 36 61 Step 2 Multiply the mass of each isotope by its decimal percentage. 63 × 0.6917 = 43.5771 65 × 0.3083 = 20.0395 Step 3 Add the values together to get the average atomic mass. 43.5771 + 20.0395 = 63.62 Practice (8 points this column) 1. Boron (B) contains 19.9% B-10 and 80.1% B-11. What is the average atomic mass of boron? 2. If 50.69% of bromine (Br) is Br-79 and 49.31% is Br-81, what is the average atomic mass of bromine? 29 Davis School District Buffalo Book Chapter 3 3. Silicon (Si) contains 92.23% Si-28, 4.67% Si-29, and 3.10% Si-30. What is the average atomic mass of Si? 4. If selenium (Se) is 0.89% Se-74, 9.36% Se-76, 7.63% Se-77, 23.78% Se78, 49.61% Se-80, and 8.73% is Se-82, what is the average atomic mass of Se? Online Physical Science Bubble Book Chapter 9 55 points this page Name____________________ Protons, Neutrons, and Electrons−How Atoms Differ Directions: Use your textbook to answer each question. (5 points each sentence) 1. Atoms are composed of particles called protons, neutrons, and electrons. Describe the relative mass, the charge, and the location within the atom of protons, neutrons, and electrons. 2. There are 115 different elements. Each has its own distinct properties. Describe the way atoms of elements differ. 3. Most elements have different isotopes. Date Period Key Concept How does a neutral atom change when its number of protons, electrons, or neutrons changes? Directions: Label this diagram by writing the correct number of electrons and protons on each line. Then use the diagram to answer each question on the lines provided. 1. 3. 2. 4. 5. 7. Identify how atoms of isotopes differ from one another. 8. 6. 4. Some elements have an unstable nucleus that changes into a more stable nucleus through nuclear decay. Identify and describe three types of nuclear decay. 9. What does the diagram show? 5. Neutral atoms sometimes gain or lose electrons. Atoms that are no longer neutral because they have gained or lost electrons are called ions. Describe the charge on an atom that has lost electrons. Then describe the charge on an atom that has gained electrons. 10. What happened to the electrical charge of each atom in the diagram? 11. The top left diagram shows sodium (Na). The bottom left diagram shows fluorine (F). Which symbols would you use to represent the top right diagram and the bottom right diagram? 6 Utah Core Curriculum Standard I Davis School District Buffalo Book Chapter 3 Online Physical Science Bubble Book Chapter 9 Name____________________ Radioisotopes Date 20 points this page You have learned that some isotopes of elements are radioactive. These are called radioisotopes. Radioisotopes are unstable, so they undergo decay by giving off radiation as matter and/or energy until they reach a more stable state. Half-Lives The rate at which radioisotopes of various elements decay is described as the half-life of the isotope. One half-life is the time it takes for one-half the atoms in a sample to decay. Half-lives for various radioisotopes can range from less than a second to billions of years. The table shows the half-lives for a number of radioisotopes. The number after each name is the isotope’s atomic mass. Radioisotope Half-life Polonium-215 0.0018 seconds Barium-139 86 minutes Iodine-131 8.07 days Cobalt-60 5.26 years Carbon-14 5,730 years Uranium-238 4.5 billion years Applying Critical-Thinking Skills 1. Solve You began with 100 g of cobalt-60. How much cobalt-60 remains after 21.04 years? 2. Explain The uranium used in fuel rods in nuclear power plants eventually decays to the point where it doesn’t give off enough energy to be practical. Why might disposing of these rods be a problem if they contain uranium-238? 3. Make a bar graph showing how much is left after Using Half-Lives Suppose you begin with 10 g of barium-139, which decays to become lanthanum-139. After one half-life (86 minutes), you would have 5 g of barium-139 and 5 g of lanthanum-139. After another 86 minutes, half of the remaining 5 g of barium-139 would decay into lanthanum-139. You would now have 2.5 g of barium-139 and 7.5 g of lanthanum-139. How can we use this idea? Carbon Dating The half-lives of radioisotopes can help scientists determine the age of very old artifacts. For example, scientists can use the half-life of carbon-14 (C-14) to determine the approximate age of organic objects that are less than 40,000 years old. All living organisms contain a fixed percentage of the radioisotope C-14. When an organism dies, the C-14 is not replaced, but it continues to decay. By determining how much of the carbon-14 remains, scientists can calculate the age of a sample. This is known as carbon dating. Isotopes with longer half-lives such as uranium-238 can be used to date older objects such as igneous rocks. 7 Utah Core Curriculum Standard I Period Davis School District Buffalo Book Chapter 3 six half-lives. 105% 90% 75% 60% 45% 30% 15% Begin 1 2 3 4 5 6 Online Physical Science Bubble Book Chapter 9 Name____________________ Date 25 points this page Understanding the Atom Directions: On the line before each statement, write correct if the statement is correct or not correct if the statement is not correct. If the statement is not correct, change the underlined word(s) to make it correct. _______ _______ _______ 1. Carbon-12, carbon-13, and carbon-14 are examples of atoms of the same element that have different numbers of neutrons. _______ 1. A proton has a charge of 1-. 2. Neutrons and protons have the same relative mass. 3. The number of electrons in an atom of an element is the element’s 2. Radioactive elements emit radiation without external force or cause. _______ atomic number. _______ _______ 4. Neutral atoms have the same number of protons and electrons. 3. Nitrogen’s number of protons is seven. _______ 5. Carbon-12 and carbon-13 are isotopes, so they have different numbers of neutrons. _______ Period Directions: On each line, write the term that correctly replaces the underlined words in each sentence. 6. The mass number of an atom can be determined by adding the number of electrons and the number of neutrons. 4. A radioactive element goes through a process in which its unstable atomic nucleus changes into another more stable nucleus by emitting radiation. _______ Key Concept How has the atomic model changed over time? Directions: Place the events in chronological order from earliest to most recent by writing a number 1 through 7 on the line before the statement that describes each event. _____ _____ J.J. Thomson investigates the electrical charges of atoms. 5. Beneath each element’s symbol on the periodic table, there is a number that provides the average mass of the element’s isotopes, weighted according to the abundance of each isotope for the element. _______ Democritus challenges the popular idea that matter is made of fire, water, air, and earth. _____ _____ _____ Niels Bohr investigates the energy level of electrons. John Dalton finds evidence to support the theory that all matter is made of 7. Uranium is an example of an element that is able to spontaneously emit radiation. _______ Scientists discover that protons and neutrons are made of quarks. James Chadwick discovers that in addition to protons, the nucleus also contains neutrons. 8 electrons. _______ Students of Ernest Rutherford conduct the gold foil experiment. atoms that cannot be divided, created, or destroyed. _____ _____ 6. Na+ and F– are examples of atoms that are no longer neutral because they have gained or lost Utah Core Curriculum Standard I 8. Carbon-12 is the most abundant isotope of the element; it has a sum of protons and neutrons equal to 12. _______ Davis School District Buffalo Book Chapter 3 Online Physical Science Bubble Book Chapter 9