Presentation is loading. Please wait.

Presentation is loading. Please wait.

Topic 2.

Similar presentations


Presentation on theme: "Topic 2."— Presentation transcript:

1 Topic 2

2 Topic 2: Atomic Structure
Table of Contents Topic 2 Topic 2: Atomic Structure Basic Concepts Additional Concepts

3 Development of the Modern Atomic Theory
Atomic Structure: Basic Concepts Topic 2 Development of the Modern Atomic Theory In 1782, a French chemist, Antoine Lavoisier ( ), made measurements of chemical change in a sealed container. He observed that the mass of reactants in the container before a chemical reaction was equal to the mass of the products after the reaction.

4 Development of the Modern Atomic Theory
Atomic Structure: Basic Concepts Topic 2 Development of the Modern Atomic Theory Lavoisier concluded that when a chemical reaction occurs, matter is neither created nor destroyed but only changed. Lavoisier’s conclusion became known as the law of conservation of matter. Click box to view movie clip.

5 Development of the Modern Atomic Theory
Atomic Structure: Basic Concepts Topic 2 Development of the Modern Atomic Theory In 1799, another French chemist, Joseph Proust, observed that the composition of water is always 11 percent hydrogen and 89 percent oxygen by mass. Regardless of the source of the water, it always contains these same percentages of hydrogen and oxygen.

6 Development of the Modern Atomic Theory
Atomic Structure: Basic Concepts Topic 2 Development of the Modern Atomic Theory Proust studied many other compounds and observed that the elements that composed the compounds were always in a certain proportion by mass. This principle is now referred to as the law of definite proportions.

7 Dalton’s Atomic Theory
Atomic Structure: Basic Concepts Topic 2 Dalton’s Atomic Theory John Dalton ( ), an English schoolteacher and chemist, studied the results of experiments by Lavoisier, Proust, and many other scientists.

8 Dalton’s Atomic Theory
Atomic Structure: Basic Concepts Topic 2 Dalton’s Atomic Theory Dalton proposed his atomic theory of matter in 1803. Although his theory has been modified slightly to accommodate new discoveries, Dalton’s theory was so insightful that it has remained essentially intact up to the present time.

9 Dalton’s Atomic Theory
Atomic Structure: Basic Concepts Topic 2 Dalton’s Atomic Theory The following statements are the main points of Dalton’s atomic theory. 1. All matter is made up of atoms. 2. Atoms are indestructible and cannot be divided into smaller particles. (Atoms are indivisible.) 3. All atoms of one element are exactly alike, but are different from atoms of other elements.

10 Hypotheses, Theories, and Laws
Atomic Structure: Basic Concepts Topic 2 Hypotheses, Theories, and Laws The first step to solving a problem, such as what makes up matter, is observation. Scientists use their senses to observe the behavior of matter at the macroscopic level.

11 Hypotheses, Theories, and Laws
Atomic Structure: Basic Concepts Topic 2 Hypotheses, Theories, and Laws They then come up with a hypothesis, which is a testable prediction to explain their observations. To find out whether a hypothesis is correct, it must be tested by repeated experiments.

12 Hypotheses, Theories, and Laws
Atomic Structure: Basic Concepts Topic 2 Hypotheses, Theories, and Laws Scientists accept hypotheses that are verified by experiments and reject hypotheses that can’t stand up to experimental testing.

13 Hypotheses, Theories, and Laws
Atomic Structure: Basic Concepts Topic 2 Hypotheses, Theories, and Laws A theory is an explanation based on many observations and supported by the results of many experiments.

14 Hypotheses, Theories, and Laws
Atomic Structure: Basic Concepts Topic 2 Hypotheses, Theories, and Laws As scientists gather more information, a theory may have to be revised or replaced with another theory.

15 Hypotheses, Theories, and Laws
Atomic Structure: Basic Concepts Topic 2 Hypotheses, Theories, and Laws A scientific law is simply a fact of nature that is observed so often that it becomes accepted as truth. A law can generally be used to make predictions but does not explain why something happens. In fact, theories explain laws.

16 Thomson’s experiments used a vacuum tube.
Atomic Structure: Basic Concepts Topic 2 The Electron Because of Dalton’s atomic theory, most scientists in the 1800s believed that the atom was like a tiny solid ball that could not be broken up into parts. In 1897, a British physicist, J.J. Thomson, discovered that this solid-ball model was not accurate. Thomson’s experiments used a vacuum tube.

17 A vacuum tube has had all gases pumped out of it.
Atomic Structure: Basic Concepts Topic 2 The Electron A vacuum tube has had all gases pumped out of it. At each end of the tube is a metal piece called an electrode, which is connected through the glass to a metal terminal outside the tube. These electrodes become electrically charged when they are connected to a high-voltage electrical source.

18 Atomic Structure: Basic Concepts
Topic 2 Cathode-Ray Tube When the electrodes are charged, rays travel in the tube from the negative electrode, which is the cathode, to the positive electrode, the anode. Because these rays originate at the cathode, they are called cathode rays.

19 Atomic Structure: Basic Concepts
Topic 2 Cathode-Ray Tube Thomson found that the rays bent toward a positively charged plate and away from a negatively charged plate. He knew that objects with like charges repel each other, and objects with unlike charges attract each other. Click box to view movie clip.

20 Atomic Structure: Basic Concepts
Topic 2 Cathode-Ray Tube Thomson concluded that cathode rays are made up of invisible, negatively charged particles referred to as electrons. These electrons had to come from the matter (atoms) of the negative electrode.

21 Atomic Structure: Basic Concepts
Topic 2 Cathode-Ray Tube From Thomson’s experiments, scientists had to conclude that atoms were not just neutral spheres, but somehow were composed of electrically charged particles. Reason should tell you that there must be a lot more to the atom than electrons. Matter is not negatively charged, so atoms can’t be negatively charged either.

22 Atomic Structure: Basic Concepts
Topic 2 Cathode-Ray Tube If atoms contained extremely light, negatively charged particles, then they must also contain positively charged particles—probably with a much greater mass than electrons.

23 These rays travel in a direction opposite to that of cathode rays.
Atomic Structure: Basic Concepts Topic 2 Protons In 1886, scientists discovered that a cathode-ray tube emitted rays not only from the cathode but also from the positively charged anode. These rays travel in a direction opposite to that of cathode rays.

24 Atomic Structure: Basic Concepts
Topic 2 Protons Like cathode rays, they are deflected by electrical and magnetic fields, but in directions opposite to the way cathode rays are deflected. Thomson was able to show that these rays had a positive electrical charge. Years later, scientists determined that the rays were composed of positively charged subatomic particles called protons.

25 However, in 1910, Thomson discovered that neon consisted
Atomic Structure: Basic Concepts Topic 2 Protons At this point, it seemed that atoms were made up of equal numbers of electrons and protons. However, in 1910, Thomson discovered that neon consisted of atoms of two different masses.

26 The third was too scarce for Thomson to detect.
Atomic Structure: Basic Concepts Topic 2 Protons Atoms of an element that are chemically alike but differ in mass are called isotopes of the element. Today, chemists know that neon consists of three naturally occurring isotopes. The third was too scarce for Thomson to detect.

27 Atomic Structure: Basic Concepts
Topic 2 Neutrons Because of the discovery of isotopes, scientists hypothesized that atoms contained still a third type of particle that explained these differences in mass. Calculations showed that such a particle should have a mass equal to that of a proton but no electrical charge. The existence of this neutral particle, called a neutron, was confirmed in the early 1930s.

28 Rutherford’s Gold Foil Experiment
Atomic Structure: Basic Concepts Topic 2 Rutherford’s Gold Foil Experiment In 1909, a team of scientists led by Ernest Rutherford in England carried out the first of several important experiments that revealed an arrangement far different from the cookie-dough model of the atom.

29 Rutherford’s Gold Foil Experiment
Atomic Structure: Basic Concepts Topic 2 Rutherford’s Gold Foil Experiment The experimenters set up a lead-shielded box containing radioactive polonium, which emitted a beam of positively charged subatomic particles through a small hole. Click box to view movie clip.

30 Rutherford’s Gold Foil Experiment
Atomic Structure: Basic Concepts Topic 2 Rutherford’s Gold Foil Experiment Today, we know that the particles of the beam consisted of clusters containing two protons and two neutrons and are called alpha particles. The sheet of gold foil was surrounded by a screen coated with zinc sulfide, which glows when struck by the positively charged particles of the beam.

31 The Gold Foil Experiment
Atomic Structure: Basic Concepts Topic 2 The Gold Foil Experiment

32 The Nuclear Model of the Atom
Atomic Structure: Basic Concepts Topic 2 The Nuclear Model of the Atom To explain the results of the experiment, Rutherford’s team proposed a new model of the atom. Because most of the particles passed through the foil, they concluded that the atom is nearly all empty space. Click box to view movie clip.

33 The Nuclear Model of the Atom
Atomic Structure: Basic Concepts Topic 2 The Nuclear Model of the Atom Because so few particles were deflected, they proposed that the atom has a small, dense, positively charged central core, called a nucleus.

34 The Nuclear Model of the Atom
Atomic Structure: Basic Concepts Topic 2 The Nuclear Model of the Atom The new model of the atom as pictured by Rutherford’s group in 1911 is shown below.

35 Atomic Structure: Basic Concepts
Topic 2 Atomic Numbers The atomic number of an element is the number of protons in the nucleus of an atom of that element. It is the number of protons that determines the identity of an element, as well as many of its chemical and physical properties.

36 Atomic Structure: Basic Concepts
Topic 2 Atomic Numbers Because atoms have no overall electrical charge, an atom must have as many electrons as there are protons in its nucleus. Therefore, the atomic number of an element also tells the number of electrons in a neutral atom of that element.

37 The mass of a neutron is almost the same as the mass of a proton.
Atomic Structure: Basic Concepts Topic 2 Masses The mass of a neutron is almost the same as the mass of a proton. The sum of the protons and neutrons in the nucleus is the mass number of that particular atom.

38 Atomic Structure: Basic Concepts
Topic 2 Masses Isotopes of an element have different mass numbers because they have different numbers of neutrons, but they all have the same atomic number.

39 Atomic Structure: Basic Concepts
Topic 2 Atomic Mass In order to have a simpler way of comparing the masses of individual atoms, chemists have devised a different unit of mass called an atomic mass unit, which is given the symbol u. An atom of the carbon-12 isotope contains six protons and six neutrons and has a mass number of 12.

40 Therefore, 1 u = 1/12 the mass of a carbon-12 atom.
Atomic Structure: Basic Concepts Topic 2 Atomic Mass Chemists have defined the carbon-12 atom as having a mass of 12 atomic mass units. Therefore, 1 u = 1/12 the mass of a carbon-12 atom. 1 u is approximately the mass of a single proton or neutron.

41 Information in the Periodic Table
Atomic Structure: Basic Concepts Topic 2 Information in the Periodic Table The number at the bottom of each box is the average atomic mass of that element. This number is the weighted average mass of all the naturally occurring isotopes of that element.

42 Atomic Structure: Basic Concepts
Topic 2 Electrons in Motion Niels Bohr ( ), a Danish scientist who worked with Rutherford, proposed that electrons must have enough energy to keep them in constant motion around the nucleus. Electrons have energy of motion that enables them to overcome the attraction of the positive nucleus.

43 This energy keeps the electrons moving around the nucleus.
Atomic Structure: Basic Concepts Topic 2 Electrons in Motion This energy keeps the electrons moving around the nucleus. Bohr’s view of the atom, which he proposed in 1913, was called the planetary model.

44 The Electromagnetic Spectrum
Atomic Structure: Basic Concepts Topic 2 The Electromagnetic Spectrum To boost a satellite into a higher orbit requires energy from a rocket motor. One way to increase the energy of an electron is to supply energy in the form of high-voltage electricity. Another way is to supply electromagnetic radiation, also called radiant energy.

45 The Electromagnetic Spectrum
Atomic Structure: Basic Concepts Topic 2 The Electromagnetic Spectrum Radiant energy travels in the form of waves that have both electrical and magnetic properties. These electromagnetic waves can travel through empty space, as you know from the fact that radiant energy from the sun travels to Earth every day.

46 The Electromagnetic Spectrum
Atomic Structure: Basic Concepts Topic 2 The Electromagnetic Spectrum As you may already have guessed, electromagnetic waves travel through space at the speed of light, which is approximately 300 million meters per second.

47 The Electromagnetic Spectrum
Atomic Structure: Basic Concepts Topic 2 The Electromagnetic Spectrum Electromagnetic radiation includes radio waves that carry broadcasts to your radio and TV, microwave radiation used to heat food in a microwave oven, radiant heat used to toast bread, and the most familiar form, visible light. All of these forms of radiant energy are parts of a whole range of electromagnetic radiation called the electromagnetic spectrum.

48 The Electromagnetic Spectrum
Atomic Structure: Basic Concepts Topic 2 The Electromagnetic Spectrum

49 Atomic Structure: Basic Concepts
Topic 2 Electrons and Light The spectrum of light released from excited atoms of an element is called the emission spectrum of that element.

50 Evidence for Energy Levels
Atomic Structure: Basic Concepts Topic 2 Evidence for Energy Levels Bohr theorized that electrons absorbed energy and moved to higher energy states. Then, these excited electrons gave off that energy as light waves when they fell back to a lower energy state.

51 Evidence for Energy Levels
Atomic Structure: Basic Concepts Topic 2 Evidence for Energy Levels Because electrons can have only certain amounts of energy, Bohr reasoned, they can move around the nucleus only at distances that correspond to those amounts of energy. These regions of space in which electrons can move about the nucleus of an atom are called energy levels.

52 The Electron Cloud Model
Atomic Structure: Basic Concepts Topic 2 The Electron Cloud Model As a result of continuing research throughout the 20th century, scientists today realize that energy levels are not neat, planetlike orbits around the nucleus of an atom. Instead, they are spherical regions of space around the nucleus in which electrons are most likely to be found.

53 The Electron Cloud Model
Atomic Structure: Basic Concepts Topic 2 The Electron Cloud Model Electrons themselves take up little space but travel rapidly through the space surrounding the nucleus. These spherical regions where electrons travel may be depicted as clouds around the nucleus. The space around the nucleus of an atom where the atom’s electrons are found is called the electron cloud.

54 The Electron Cloud Model
Atomic Structure: Basic Concepts Topic 2 The Electron Cloud Model

55 Electrons in Energy Level
Atomic Structure: Basic Concepts Topic 2 Electrons in Energy Level How are electrons arranged in energy levels? Each energy level can hold a limited number of electrons. The lowest energy level is the smallest and the closest to the nucleus.

56 Electrons in Energy Level
Atomic Structure: Basic Concepts Topic 2 Electrons in Energy Level This first energy level holds a maximum of two electrons. The second energy level is larger because it is farther away from the nucleus. It holds a maximum of eight electrons. The third energy level is larger still and holds a maximum of 18 electrons.

57 A hydrogen atom has only one electron. It’s in the first energy level.
Atomic Structure: Basic Concepts Topic 2 Energy Levels A hydrogen atom has only one electron. It’s in the first energy level.

58 Electrons in Energy Level
Atomic Structure: Basic Concepts Topic 2 Electrons in Energy Level The electrons in the outermost energy level are called valence electrons. You can also use the periodic table as a tool to predict the number of valence electrons in any atom in Groups 1, 2, 13, 14, 15, 16, 17, and 18. All atoms in Group 1, like hydrogen, have one valence electron. Likewise, atoms in Group 2 have two valence electrons.

59 Electrons in Energy Level
Atomic Structure: Basic Concepts Topic 2 Electrons in Energy Level An oxygen atom has eight electrons. Two of these fill the first energy level, and the remaining six are in the second energy level.

60 Atomic Structure: Basic Concepts
Topic 2 Lewis Dot Diagrams Because valence electrons are so important to the behavior of an atom, it is useful to represent them with symbols.

61 Atomic Structure: Basic Concepts
Topic 2 Lewis Dot Diagrams A Lewis dot diagram illustrates valence electrons as dots (or other small symbols) around the chemical symbol of an element.

62 Each dot represents one valence electron.
Atomic Structure: Basic Concepts Topic 2 Lewis Dot Diagrams Each dot represents one valence electron. In the dot diagram, the element’s symbol represents the core of the atom—the nucleus plus all the inner electrons.

63 Basic Concept Questions
Topic 2 Question 1 How does the atomic number of an element differ from the element’s mass number? Answer The atomic number of an element is the number of protons in the nucleus. The mass number is the sum of the number of protons and neutrons.

64 Question 2 Write a Lewis dot diagram for each of the following.
Basic Concept Questions Topic 2 Question 2 Write a Lewis dot diagram for each of the following. A. Chlorine B. Calcium C. Potassium

65 Answer A. Chlorine B. Calcium C. Potassium Topic 2
Basic Concept Questions Topic 2 Answer A. Chlorine B. Calcium C. Potassium

66 Basic Concept Questions
Topic 2 Question 3 Give an example for each type of electromagnetic energy listed below. A. Ultraviolet light B. Infrared light C. Visible light

67 Answer Sample answers: A. ultraviolet light: part of sunlight
Basic Concept Questions Topic 2 Answer Sample answers: A. ultraviolet light: part of sunlight B. infrared light: radiant heat C. visible light: the spectrum of light we see as color

68 Atomic Structure: Additional Concepts
Topic 2 Additional Concepts

69 Energy Levels and Sublevels
Atomic Structure: Additional Concepts Topic 2 Energy Levels and Sublevels The emission spectrum for each element has a characteristic set of spectral lines. This means that the energy levels within the atom must also be characteristic of each element. But when scientists investigated multi-electron atoms, they found that their spectra were far more complex than would be anticipated by the simple set of energy levels predicted for hydrogen.

70 Energy Levels and Sublevels
Atomic Structure: Additional Concepts Topic 2 Energy Levels and Sublevels Notice that these spectra have many more lines than the spectrum of hydrogen.

71 Energy Levels and Sublevels
Atomic Structure: Additional Concepts Topic 2 Energy Levels and Sublevels Some lines are grouped close together, and there are big gaps between these groups of lines.

72 Energy Levels and Sublevels
Atomic Structure: Additional Concepts Topic 2 Energy Levels and Sublevels The big gaps correspond to the energy released when an electron jumps from one energy level to another.

73 Energy Levels and Sublevels
Atomic Structure: Additional Concepts Topic 2 Energy Levels and Sublevels The interpretation of the closely spaced lines is that they represent the movement of electrons from levels that are not very different in energy. This suggests that sublevels—divisions within a level—exist within a given energy level.

74 Energy Levels and Sublevels
Atomic Structure: Additional Concepts Topic 2 Energy Levels and Sublevels If electrons are distributed over one or more sublevels within an energy level, then these electrons would have only slightly different energies. The energy sublevels are designated as s, p, d, or f.

75 Energy Levels and Sublevels
Atomic Structure: Additional Concepts Topic 2 Energy Levels and Sublevels Each energy level has a specific number of sublevels, which is the same as the number of the energy level. For example, the first energy level has one sublevel. It’s called the 1s sublevel. The second energy level has two sublevels, the 2s and 2p sublevels

76 Energy Levels and Sublevels
Atomic Structure: Additional Concepts Topic 2 Energy Levels and Sublevels The third energy level has three sublevels: the 3s, 3p, and 3d sublevels; and the fourth energy level has four sublevels: the 4s, 4p, 4d, and 4f sublevels. Within a given energy level, the energies of the sublevels, from lowest to highest, are s, p, d, and f.

77 The Distribution of Electrons in Energy Levels
Atomic Structure: Additional Concepts Topic 2 The Distribution of Electrons in Energy Levels A specific number of electrons can go into each sublevel.

78 The Distribution of Electrons in Energy Levels
Atomic Structure: Additional Concepts Topic 2 The Distribution of Electrons in Energy Levels An s sublevel can have a maximum of two electrons, a p sublevel can have six electrons,

79 The Distribution of Electrons in Energy Levels
Atomic Structure: Additional Concepts Topic 2 The Distribution of Electrons in Energy Levels a d sublevel can have ten electrons, and an f sublevel can have 14 electrons.

80 Atomic Structure: Additional Concepts
Topic 2 Orbitals In the 1920s, Werner Heisenberg reached the conclusion that it’s impossible to measure accurately both the position and energy of an electron at the same time. This principle is known as the Heisenberg uncertainty principle. In 1932, Heisenberg was awarded the Nobel Prize in Physics for this discovery, which led to the development of the electron cloud model to describe electrons in atoms.

81 Atomic Structure: Additional Concepts
Topic 2 Orbitals The electron cloud model is based on the probability of finding an electron in a certain region of space at any given instant. In any atom, electrons are distributed into sublevels and orbitals in the way that creates the most stable arrangement; that is, the one with lowest energy.

82 Electron Configurations
Atomic Structure: Additional Concepts Topic 2 Electron Configurations This most stable arrangement of electrons in sublevels and orbitals is called an electron configuration. Electrons fill orbitals and sublevels in an orderly fashion beginning with the innermost sublevels and continuing to the outermost.

83 Orbitals and the Periodic Table
Atomic Structure: Additional Concepts Topic 2 Orbitals and the Periodic Table The shape of the modern periodic table is a direct result of the order in which electrons fill energy sublevels and orbitals. The periodic table is divided into blocks that show the sublevels and orbitals occupied by the electrons of the atoms.

84 Orbitals and the Periodic Table
Atomic Structure: Additional Concepts Topic 2 Orbitals and the Periodic Table Notice that Groups 1 and 2 (the active metals) have valence electrons in s orbitals, and Groups 13 to 18 (metals, metalloids, and nonmetals) have valence electrons in both s and p orbitals.

85 Building Electron Configurations
Atomic Structure: Additional Concepts Topic 2 Building Electron Configurations Chemical properties repeat when elements are arranged by atomic number because electron configurations repeat in a certain pattern. As you move through the table, you’ll notice how an element’s position is related to its electron configuration.

86 Building Electron Configurations
Atomic Structure: Additional Concepts Topic 2 Building Electron Configurations Hydrogen has a single electron in the first energy level. Its electron configuration is 1s1. This is standard notation for electron configurations. The number 1 refers to the energy level, the letter s refers to the sublevel, and the superscript refers to the number of electrons in the sublevel.

87 Building Electron Configurations
Atomic Structure: Additional Concepts Topic 2 Building Electron Configurations Helium has two electrons in the 1s orbital. Its electron configuration is 1s2. Helium has a completely filled first energy level. When the first energy level is filled, additional electrons must go into the second energy level.

88 Building Electron Configurations
Atomic Structure: Additional Concepts Topic 2 Building Electron Configurations Lithium begins the second period. Its first two electrons fill the first energy level, so the third electron occupies the second level. Lithium’s electron configuration is 1s22s1. Beryllium has two electrons in the 2s orbital, so its electron configuration is 1s22s2 .

89 Building Electron Configurations
Atomic Structure: Additional Concepts Topic 2 Building Electron Configurations As you continue to move across the second period, electrons begin to enter the p orbitals. Each successive element has one more electron in the 2p orbitals. Carbon, for example, has four electrons in the second energy level. Two of these are in the 2s orbital and two are in the 2p orbitals. The electron configuration for carbon is 1s22s22p2.

90 Building Electron Configurations
Atomic Structure: Additional Concepts Topic 2 Building Electron Configurations

91 Building Electron Configurations
Atomic Structure: Additional Concepts Topic 2 Building Electron Configurations At element number 10, neon, the p sublevel is filled with six electrons. The electron configuration for neon is 1s22s22p6. Neon has eight valence electrons; two are in an s orbital and six are in p orbitals.

92 Building Electron Configurations
Atomic Structure: Additional Concepts Topic 2 Building Electron Configurations Notice that neon’s configuration has an inner core of electrons that is identical to the electron configuration in helium (1s2). This insight simplifies the way electron configurations are written. Neon’s electron configuration can be abbreviated: [He]2s22p6.

93 Building Electron Configurations
Atomic Structure: Additional Concepts Topic 2 Building Electron Configurations Notice that elements in the same group have similar configurations. This is important because it shows that the periodic trends in properties, observed in the periodic table, are really the result of repeating patterns of electron configuration.

94 Building Electron Configurations
Atomic Structure: Additional Concepts Topic 2 Building Electron Configurations

95 Atomic Structure: Additional Concepts
Topic 2 Noble Gases Each period ends with a noble gas, so all the noble gases have filled energy levels and, therefore, stable electron configurations.

96 Atomic Structure: Additional Concepts
Topic 2 Noble Gases These stable electron configurations explain the lack of reactivity of the noble gases. Noble gases don’t need to form chemical bonds to acquire stability.

97 Atomic Structure: Additional Concepts
Topic 2 Transition Elements Notice in the periodic table that calcium is followed by a group of ten elements beginning with scandium and ending with zinc. These are transition elements. Now the 3d sublevel begins to fill, producing atoms with the lowest possible energy.

98 Atomic Structure: Additional Concepts
Topic 2 Transition Elements Like most metals, the transition elements lose electrons to attain a more stable configuration.

99 Inner Transition Elements
Atomic Structure: Additional Concepts Topic 2 Inner Transition Elements The two rows beneath the main body of the periodic table are the lanthanides (atomic numbers 58 to 71) and the actinides (atomic numbers 90 to 103). These two series are called inner transition elements because their last electron occupies inner-level 4f orbitals in the sixth period and the 5f orbitals in the seventh period.

100 Calculating Atomic Mass
Atomic Structure: Additional Concepts Topic 2 Calculating Atomic Mass

101 Calculating Atomic Mass
Atomic Structure: Additional Concepts Topic 2 Calculating Atomic Mass Copper exists as a mixture of two isotopes. The lighter isotope (Cu-63), with 29 protons and 34 neutrons, makes up 69.17% of copper atoms. The heavier isotope (Cu-65), with 29 protons and 36 neutrons, constitutes the remaining 30.83% of copper atoms.

102 Calculating Atomic Mass
Atomic Structure: Additional Concepts Topic 2 Calculating Atomic Mass The atomic mass of Cu-63 is amu, and the atomic mass of Cu-65 is amu. Use the data above to compute the atomic mass of copper.

103 Calculating Atomic Mass
Atomic Structure: Additional Concepts Topic 2 Calculating Atomic Mass First, calculate the contribution of each isotope to the average atomic mass, being sure to convert each percent to a fractional abundance.

104 Calculating Atomic Mass
Atomic Structure: Additional Concepts Topic 2 Calculating Atomic Mass The average atomic mass of the element is the sum of the mass contributions of each isotope.

105 Additional Assessment Questions
Topic 2 Question 1 Write electron configurations and abbreviated electron configurations of the following elements. A. Boron B. Fluorine C. Phosphorus

106 Answer A. Boron B. Fluorine C. Phosphorus Topic 2
Additional Assessment Questions Topic 2 Answer A. Boron B. Fluorine C. Phosphorus

107 Additional Assessment Questions
Topic 2 Question 2 The table on the next slide shows the five isotopes of germanium found in nature, the abundance of each isotope, and the atomic mass of each isotope.

108 Calculate the atomic mass of germanium.
Additional Assessment Questions Topic 2 Calculate the atomic mass of germanium.

109 Additional Assessment Questions
Topic 2 Answer 72.59 amu

110 Help Topic 2 To advance to the next item or next page click on any of the following keys: mouse, space bar, enter, down or forward arrow. Click on this icon to return to the table of contents Click on this icon to return to the previous slide Click on this icon to move to the next slide Click on this icon to open the resources file. Click on this icon to go to the end of the presentation.

111 End of Topic Summary File
2 End of Topic Summary File


Download ppt "Topic 2."

Similar presentations


Ads by Google