Matter Is Made Up of Atoms CHAPTER

Transcription

1 Reviewing Vocabulary Complete each statement 1 In science, a testable prediction to explain observations is known as a(n) The neutral particle found within an atom is the 3 The sum of the protons and neutrons in the nucleus of an atom is called the of that atom 4 The space around the nucleus of an atom where the atom s electrons are found is called the 5 The is the positively charged central core of an atom 6 A system used to represent the valence electrons around the chemical symbol of an element is the 7 The positively-charged, subatomic particle is a(n) 8 According to the, the elements that make up a compound always occur in the same mass proportion 9 A fact of nature that has been confirmed many times by observation is known as a(n) 10 The range of all forms of radiant energy is given the name 11 A(n) is the region of space where electrons of a certain energy move about the nucleus of an atom 1 The smallest particle of which matter consists is a(n) 13 A(n) is found in the outermost energy level of an atom 14 The number of protons in the nucleus of an atom of an element is the of that element 15 The is the idea that matter is made up of fundamental particles called atoms 16 A negatively charged particle found in all atoms is the Chemistry: Concepts and Applications, Chapter 11

2 Understanding Concepts Part A In the space at the left, write the letter of the word or phrase that best completes the statement or answers the question 1 The first subatomic particle discovered was the a proton c electron b neutron d nucleus The scientific statement that says that compounds always have exactly the same composition by mass is the a atomic theory c law of conservation of matter b matter hypothesis d law of definite proportions 3 When a hypothesis is tested by many experiments, it becomes a(n) a scientific law c theory b revised hypothesis d experimental fact 4 The only subatomic particle that does not carry an electric charge is the a proton c electron b neutron d nucleus 5 The atomic number of an element whose atoms have 9 protons and 10 neutrons is a 9 c 10 b 19 d 18 6 The mass number of an element whose atoms have 1 protons and 13 neutrons is a 1 c 5 b 13 d 15 7 One isotope of carbon has 6 protons and 6 neutrons The number of protons and neutrons of a second isotope of carbon would be a 7 and 6 c 7 and 7 b 6 and 7 d 6 and 6 8 The correct way to arrange the three forms of electromagnetic radiation listed below, from highest to lowest frequency, is a ultraviolet > visible > infrared c infrared > visible > ultraviolet b visible > ultraviolet > infrared d infrared > ultraviolet > visible 1 Chemistry: Concepts and Applications, Chapter

3 Understanding Concepts Part B The three boxes below are taken from the periodic table They represent elements that have no known isotopes Use the information contained in these boxes to supply the information requested for the atoms of each element For atomic structure, give the number of protons, neutrons, and electrons Beryllium 4 Be 901 Scandium 1 Sc Manganese 5 Mn Beryllium: Mass number for this atom: Atomic structure: Scandium: Mass number for this atom: Atomic structure: 3 Manganese: Mass number for this atom: Atomic structure: Answer the following questions 4 How did Thomson s discovery of neon s isotopes lead to the discovery of neutrons? 5 Why is it difficult to detect the presence of isotopes of an element during chemical studies? 6 How is the movement of electrons between energy levels like climbing a ladder? Chemistry: Concepts and Applications, Chapter 13

4 Thinking Critically The diagram below represents a potassium atom Answer the following questions about the electron transitions that take place in this atom 1 How many valence electrons does this atom have? Draw a Lewis dot diagram for this atom e 8e 8e 1e 3 Suppose you wanted to observe an emission spectrum for this atom How would you produce such a spectrum? Explain how this action would produce a spectrum 4 Suppose that a potassium atom absorbs energy that causes two electrons to move up to the fifth energy level: one from the fourth energy level and one from the third In terms of emission spectra, what will happen when the electrons return to their original leveles? 5 If enough energy was added to the atom to permit an electron to escape from the atom, which electron would it be? 14 Chemistry: Concepts and Applications, Chapter

5 Interpreting Data and Lab Skills The table below contains a set of data similar to those on which Joseph Louis Proust based his law of definite proportions in 1799 Answer the following questions about these data and their interpretation Trial Nitrogen Oxygen Mass Percentage Mass Percentage g 160 g g 9 g g 3 g g 36 g 1 Calculate the percentage of nitrogen and oxygen for each of the four trials shown here How do the results of these experiments lead to the law of definite proportions? 3 How are the law of definite proportions and the atomic theory related to each other? 4 To the nearest whole number, the atomic masses of nitrogen and oxygen are 14 and 16, respectively Calculate the percentage composition of a compound made by combining one atom of nitrogen with one atom of oxygen 5 Assign a chemical formula to the compound formed between nitrogen and oxygen in question 4 Chemistry: Concepts and Applications, Chapter 15

6 Performance Assessment Chemists are sometimes portrayed as dry, uninteresting men and women, but this portrayal is seldom true The individuals who made great discoveries and inventions in chemistry often led fascinating personal lives Select any one of the famous chemists mentioned in this chapter or others who worked with them, and find out more about that person s life Concentrate on the kind of person the chemist was, what his or her personal life was like Pay special attention in your research to John Dalton Lise Meitner personality traits or events in the person s life that would be of interest to anyone, whether he or she was studying chemistry or not Consult your librarian about possible sources of biographical information on these individuals Some useful resources are listed at the bottom of this page Summarize what you have learned by writing a short story or a brief play about A Day in the Life of Read your story or present your play to a group of non-chemistry students and see what their reactions are to the person whose life you have portrayed 16 Chemistry: Concepts and Applications, Chapter