1. < BackNext >PreviewMain Introduction to Atoms Preview Chapter 11 CRCT Preparation

2. < BackNext >PreviewMain CRCT Preparation Chapter 11 1. What principle of electromagnetic force is depicted in the above diagram of an atom? A Particles with the same charges have no effect on each other. B Particles with opposite charges attract each other. C Electromagnetic force repels objects from the nucleus. D Protons and neutrons repel each other because they have the same charge.

3. < BackNext >PreviewMain CRCT Preparation Chapter 11 1. What principle of electromagnetic force is depicted in the above diagram of an atom? A Particles with the same charges have no effect on each other. B Particles with opposite charges attract each other. C Electromagnetic force repels objects from the nucleus. D Protons and neutrons repel each other because they have the same charge.

4. < BackNext >PreviewMain Chapter 11 CRCT Preparation 2. What is the key difference that causes the atoms of one element to differ from the atoms of all other elements? A the number of electrons B the number of isotopes C the number of neutrons D the number of protons

5. < BackNext >PreviewMain Chapter 11 CRCT Preparation 2. What is the key difference that causes the atoms of one element to differ from the atoms of all other elements? A the number of electrons B the number of isotopes C the number of neutrons D the number of protons

6. < BackNext >PreviewMain Chapter 11 3. Atom A contains 8 protons and 8 neutrons. Atom B contains 8 protons and 9 neutrons. Which of the following statements correctly describes the two atoms? A They are isotopes. B They are radioactive. C They are atoms of different elements. D They have the same mass number. CRCT Preparation

7. < BackNext >PreviewMain Chapter 11 CRCT Preparation 3. Atom A contains 8 protons and 8 neutrons. Atom B contains 8 protons and 9 neutrons. Which of the following statements correctly describes the two atoms? A They are isotopes. B They are radioactive. C They are atoms of different elements. D They have the same mass number.

8. < BackNext >PreviewMain Chapter 11 4. Which of the following pieces of equipment was J. J. Thomson using when he discovered electrons? A electron microscope B magnifying lens C cathode-ray tube D telescope CRCT Preparation

9. < BackNext >PreviewMain Chapter 11 CRCT Preparation 4. Which of the following pieces of equipment was J. J. Thomson using when he discovered electrons? A electron microscope B magnifying lens C cathode-ray tube D telescope

10. < BackNext >PreviewMain Chapter 11 CRCT Preparation 5. Which of the following statements about the mass of a neutron is true? A A neutron has half the mass of a proton. B A neutron is a little more massive than a proton. C A neutron has the same mass as an electron. D A neutron is a little less massive than an electron.

11. < BackNext >PreviewMain Chapter 11 CRCT Preparation 5. Which of the following statements about the mass of a neutron is true? A A neutron has half the mass of a proton. B A neutron is a little more massive than a proton. C A neutron has the same mass as an electron. D A neutron is a little less massive than an electron.

12. < BackNext >PreviewMain Chapter 11 6. A neutral atom has an atomic number of 20 and a mass number of 42. How many electrons does the atom have? A 20 B 22 C 42 D 62 CRCT Preparation

13. < BackNext >PreviewMain Chapter 11 CRCT Preparation 6. A neutral atom has an atomic number of 20 and a mass number of 42. How many electrons does the atom have? A 20 B 22 C 42 D 62

14. < BackNext >PreviewMain Chapter 11 7. According to the table, which of the following sets of particles has no charge? A 6 protons, 5 neutrons, 4 electrons B 5 protons, 6 neutrons, 5 electrons C 4 protons, 4 neutrons, 6 electrons D 6 protons, 5 neutrons, 5 electrons CRCT Preparation

15. < BackNext >PreviewMain Chapter 11 7. According to the table, which of the following sets of particles has no charge? A 6 protons, 5 neutrons, 4 electrons B 5 protons, 6 neutrons, 5 electrons C 4 protons, 4 neutrons, 6 electrons D 6 protons, 5 neutrons, 5 electrons CRCT Preparation

16. < BackNext >PreviewMain Chapter 11 8. According to the table, about how much mass would a nucleus that is composed of 15 protons and 18 neutrons have? A 15 amu B 18 amu C 23 amu D 33 amu CRCT Preparation

17. < BackNext >PreviewMain Chapter 11 CRCT Preparation 8. According to the table, about how much mass would a nucleus that is composed of 15 protons and 18 neutrons have? A 15 amu B 18 amu C 23 amu D 33 amu

18. < BackNext >PreviewMain Chapter 11 CRCT Preparation 9. According to the table, which of the following statements about the mass of subatomic particles is true? A The particles found in the nucleus are much more massive than the particles found in the electron cloud. B Protons and electrons have about the same mass. C Neutrons are much less massive than protons and electrons. D The positively-charged particles in the nucleus are much more massive than the neutral particles in the nucleus.

19. < BackNext >PreviewMain Chapter 11 CRCT Preparation 9. According to the table, which of the following statements about the mass of subatomic particles is true? A The particles found in the nucleus are much more massive than the particles found in the electron cloud. B Protons and electrons have about the same mass. C Neutrons are much less massive than protons and electrons. D The positively-charged particles in the nucleus are much more massive than the neutral particles in the nucleus.

20. < BackNext >PreviewMain Chapter 11 10. What would an atom of aluminum that has 13 protons and 15 neutrons be named? A aluminum-13 B aluminum-15 C aluminum-26 D aluminum-28 CRCT Preparation

21. < BackNext >PreviewMain Chapter 11 CRCT Preparation 10. What would an atom of aluminum that has 13 protons and 15 neutrons be named? A aluminum-13 B aluminum-15 C aluminum-26 D aluminum-28

22. < BackNext >PreviewMain Chapter 11 CRCT Preparation 11. Oxygen has an atomic number of 8. Which of the following could form the nucleus of an isotope of oxygen? A 4 protons and 4 neutrons B 6 protons and 8 neutrons C 8 protons and 10 neutrons D 6 protons and 2 neutrons

23. < BackNext >PreviewMain Chapter 11 CRCT Preparation 11. Oxygen has an atomic number of 8. Which of the following could form the nucleus of an isotope of oxygen? A 4 protons and 4 neutrons B 6 protons and 8 neutrons C 8 protons and 10 neutrons D 6 protons and 2 neutrons

24. < BackNext >PreviewMain Chapter 11 12. John Dalton, a British chemist, published his atomic theory in 1803. What were the three main points of Dalton’s theory? Which of those points were eventually shown to be incorrect? CRCT Preparation

25. < BackNext >PreviewMain Chapter 11 12. Answer - Full-credit answers should include the following points: All substances are made of atoms. Atoms are small particles that cannot be created, divided, or destroyed. Atoms of the same element are exactly alike, and atoms of different elements are different. Atoms join with other atoms to make new substances. The idea that atoms cannot be divided was shown to be incorrect when subatomic particles were discovered. Atoms can also be created or destroyed during nuclear changes. The idea that atoms of the same element are exactly alike was shown to be incorrect. Isotopes of an element have different numbers of neutrons in them. CRCT Preparation

26. < BackNext >PreviewMain CRCT Preparation Chapter 11 13. The interactions of four fundamental forces can describe all the physical relationships in nature. Describe these four forces and explain how they contribute to the structure of an atom.

27. < BackNext >PreviewMain CRCT Preparation Chapter 11 13. Answer - Full-credit answers should include the following points: Gravitational force is a force of attraction between objects because of their masses. A small gravitational force pulls the particles of an atom together. Electromagnetic force is a force between charged objects. Protons and electrons are attracted to each other because they have opposite charges. The electromagnetic force holds the electrons around the nucleus and repels protons from one another. The strong force is a force that holds the particles in nuclei together. Without the strong force, the protons in a nucleus would fly apart because of the electromagnetic force. The weak nuclear force is an important force in radioactive atoms. The weak force plays a key role in the change of a neutron into a proton and an electron.