Chapter 6. Electronic Structure of Atoms

Chapter 6 Electronic Structure of Atoms

Electronic Structure Electronic structure the arrangement and energy of electrons 1 st lets talk about waves Why? Extremely small particles have properties that can only be explained by learning about waves 2

Waves Wavelength ( ) Distance between corresponding points on adjacent waves is the Frequency ( ) Number of waves passing a given point per unit of time is the 2015 Pearson Education, Inc. 3

Waves Frequency ( ) Waves traveling at the same velocity Wavelength inversely proportional to frequency 1/ Ȣ Units is s -1 Measure by counting number of waves passing through a certain point What is the frequency of the figures if time is 1 second? Figure (a): 2 s 1 Figure (b): 4 s 1 2015 Pearson Education, Inc. 4

Electromagnetic Radiation Understanding the nature of electromagnetic radiation helps to understand the electronic structure of atoms Electromagnetic radiation Form of energy Called radiant energy or optical energy Different types Propagating (moving) forms of energy Wavelike characteristics Travel at the speed of light (c) is 3.00 10 8 m/s c = http://images.wisegeek.com/electromagnetic-spectrum-with-gamma-rays.jpg 5

Example Wavelength and Frequency Calculate the wavelength (in nm) of the red light emitted by a barcode scanner that has a frequency of 4.62 10 14 s 1. Solution You are given the frequency of the light and asked to find its wavelength. GIVEN = 4.26 x 10 14 s -1 FIND wavelength Use the equation that relates speed of light to frequency and wavelength and solve for wavelength. You can convert the wavelength from meters to nanometers by using the conversion factor between the two (1 nm = 10 9 m). 6

The Nature of Energy Wave nature of light does not explain how an object can glow when its temperature increases 2015 Pearson Education, Inc. 7

The Nature of Energy Quanta Max Planck explained Energy is quantized subdivide into small but measurable increments Energy comes in packets called quanta (singular: quantum) Energy can be gained or lost only in whole number multiples of h h is Planck s constant h = 6.626 x 10-34 J. s DE = h 2015 Pearson Education, Inc. 8

The Photoelectric Effect Observations about the photoelectric effect Metal emits electrons upon exposure to electromagnetic radiation Each metal has a frequency at which it ejects electrons At lower frequency, electrons are not emitted At higher frequency Emittance of electrons increases with light intensity Kinetic energy of emitted electrons increases linearly with frequency of light 2015 Pearson Education, Inc. Copyright Cengage Learning. All rights reserved 9

The Photoelectric Effect Albert Einstien Proposed electromagnetic radiation is quantized View electromagnetic radiation as particles called photons Energy of each photon E = h E = hc/ h is Planck s constant, 6.626 10 34 J s 2015 Pearson Education, Inc. 10

The Photoelectric Effect Albert Einstien Energy has dual nature of light Has properties of wave and particulate matter Known as wave-particle duality Energy has mass E =mc 2 Mass of photon m =h/ c Copyright Cengage Learning. All rights reserved 11

Example Photon Energy A nitrogen gas laser pulse with a wavelength of 337 nm contains 3.83 mj of energy. How many photons does it contain? SORT You are given wavelength and total energy of a light pulse and asked to find the number of photons it contains. STRATEGIZE In the first part of the conceptual plan, calculate the energy of an individual photon from its wavelength. GIVEN E pulse = 3.83 mj λ = 337 nm FIND number of of photons CONCEPTUAL PLAN In the second part, divide the total energy of the pulse by the energy of each photon to determine the number of photons in the pulse (because the total energy of the pulse is equal to the sum of the energies of each photon). RELATIONSHIPS USED E = hc/λ 12

Example Photon Energy (continued) SOLVE To execute the first part of the conceptual plan, convert the wavelength to meters and substitute it into the equation to calculate the energy of a 337-nm photon. To execute the second part of the conceptual plan, convert the energy of the pulse from mj to J. SOLUTION E pulse = Then divide the energy of the pulse by the energy of a photon to obtain the number of photons. 13

The Wave Nature of Matter Louis de Broglie Theorized that matter should exhibit wave properties Demonstrated the relationship between mass and wavelength The wave nature of light is used to produce this electron micrograph = h mv 2015 Pearson Education, Inc. 14

Example De Broglie Wavelength Calculate the wavelength of an electron traveling with a speed of 2.65 10 6 m/s. SORT You are given the speed of an electron and asked to calculate its wavelength. STRATEGIZE The conceptual plan shows how the de Broglie relation relates the wavelength of an electron to its mass and velocity. SOLVE Substitute the velocity, Planck s constant, and the mass of an electron into de Broglie relation to calculate the electron s wavelength. To correctly cancel the units, break down the J in Planck s constant into its SI base units (1 J = 1 kg m 2 /s 2 ). GIVEN ν = 2.65 10 6 m/s. FIND λ CONCEPTUAL PLAN RELATIONSHIPS USED λ = h/mv (de Broglie relation) SOLUTION 15

Atomic Emissions How do atoms and molecules emit energy? 2015 Pearson Education, Inc. 16

Continuous vs. Line Spectra Continuous spectrum Spectrum that contains all wave-lengths in a specified region of the electromagnetic spectrum Rainbow from a white light source Line spectrum Only discrete wavelengths is observed Each element has a unique line spectrum 2015 Pearson Education, Inc. 17

The Hydrogen Spectrum There are four lines in the hydrogen spectrum What does this mean? Only certain energies are allowed for the electron in the hydrogen atom Energy of the electron in the hydrogen atom is quantized 2015 Pearson Education, Inc. 18

Concept Check 1. Why is it significant that the color emitted from the hydrogen emission spectrum is not white? Shows that it is not a continuous spectrum. If continuous we would see a white light, which contains all colors. 2. How does the emission spectrum support the idea of quantized energy levels? Since only certain colors are observed, this means that only certain energy levels are allowed. An electron can exist at one level or another, and there are regions of zero probability in between. 19

The Bohr Model Niels Bohr adopted Planck s assumption and explained these phenomena in this way: 1. Electrons in an atom can only occupy certain circular orbitals (corresponding to certain energies) Copyright Cengage Learning. All rights reserved 20

The Bohr Model 2. Electrons in permitted orbits have specific, allowed energies 3. Energy is only absorbed or emitted in such a way as to move an electron from one allowed energy state to another 2015 Pearson Education, Inc. 21

The Bohr Model 2. Electrons in permitted orbits have specific, allowed energies 3. Energy is only absorbed or emitted in such a way as to move an electron from one allowed energy state to another 2015 Pearson Education, Inc. 22

Bohr Model Limitations Only works for hydrogen Circular motion is not wave-like in nature Points that are incorporated into the current atomic model include the following: 1) Electrons exist in discrete energy levels 2) Energy is involved in the transition of an electron from one level to another 23

QUANTUM MECHANICAL MODEL OF THE ATOM 24

The Uncertainty Principle Heisenberg showed you can not know both position and momentum of a particle (Dx) (Dmv) h 4 2015 Pearson Education, Inc. 25

Quantum Mechanics Quantum mechanics Developed by Erwin Schrödinger Mathematical equation which includes both the wave and particle nature of matter Solution of Schrödinger s wave equation is designated with a lowercase Greek psi ( ). 2, gives the electron density, or probability of where an electron is likely to be at any given time 2015 Pearson Education, Inc. 26

Quantum Numbers Quantum numbers describe the orbital Set of three Principal quantum number (n) Angular momentum quantum number (l) Magnetic quantum number (m l ) 27

Principal Quantum Number (n) Principal quantum number (n) Known as the electron shell Describes the energy level on which the orbital resides Correspond to the values in the Bohr model The values of n are integers 1 As n increases the electron is less tightly bound to the nucleus 3 rd shell 2 nd shell 1 st shell Nucleus 28

Angular Momentum Quantum Number (l) Angular momentum quantum number Called the subshell Defines the shape of the orbital Values of l are integers ranging from 0 to n 1 Use letter designations to communicate the different values of l, therefore, the shapes and types of orbitals 29

Magnetic Quantum Number (m l ) Magnetic quantum number describes the three-dimensional orientation of the orbital Allowed values of m l are integers ranging from l to l: l m l l Determines number of electron orbitals in each subshell Therefore, on any given energy level, there can be up to 1 s orbital, 3 p orbitals, 5 d orbitals, 7 f orbitals, and so forth 30

Magnetic Quantum Number (m l ) 2015 Pearson Education, Inc. 31

Example Quantum Numbers I What are the quantum numbers and names (for example, 2s, 2p) of the orbitals in the n = 4 principal level? How many n = 4 orbitals exist? Solution You first determine the possible n = 4; therefore l = 0, 1, 2, and 3 values of l (from the given value of n). You then determine the possible values of m l for each possible value of l. For a given value of n, the possible values of l are 0, 1, 2,..., (n 1). For a given value of l, the possible values of m l are the integer values including zero ranging from l to +l. The name of an orbital is its principal quantum number (n) followed by the letter corresponding to the value l. 32

ORBITAL SHAPES AND ENERGIES 33

s Orbitals s orbitals Value of l is 0 Spherical in shape Radius of the sphere increases with the value of n 2015 Pearson Education, Inc. 34

s Orbitals For an ns orbital Number of peaks is n Number of nodes is n 1 Node is where there is zero probability of finding an electron As n increases Electron density is more spread out Greater probability of finding an electron further from the nucleus 2015 Pearson Education, Inc. 35

p Orbitals p orbitals Value of l for p orbitals is 1 Composed of two lobes with a node between them 2015 Pearson Education, Inc. 36

d Orbitals d orbitals Value of l is 2 Four of the five d orbitals have four lobes Fifth resembles a p orbital with a doughnut around the center 2015 Pearson Education, Inc. 37

f Orbitals f orbitals Value of l is 3 Seven equivalent orbitals in a sublevel Copyright Cengage Learning. All rights reserved 38

Energies of Orbitals Hydrogen For hydrogen atom Orbitals on the same energy level have the same energy Called degenerate orbitals 2015 Pearson Education, Inc. 39

Energies of Orbitals Many-electron Atoms Atoms with more than one electron Not all orbitals on the same energy level are degenerate As number of electrons increase so does the repulsion between them Energy levels start to overlap in energy 4s is lower in energy than 3d 2015 Pearson Education, Inc. 40

Energies of Orbitals 41

Spin Magnetic Quantum Number, m s Spin Magnetic Quantum Number Fourth quantum number Two electrons in the same orbital do not have exactly the same energy Two allowed values, +½ and ½ The spin of an electron describes its magnetic field 2015 Pearson Education, Inc. 42

Pauli Exclusion Principle Pauli Exclusion Principle No two electrons in the same atom can have exactly the same energy No two electrons in the same atom can have identical sets of quantum numbers Every electron in an atom must differ by at least one of the four quantum number values: n, l, m l, and m s 43

STOP 44

Chapter 7 Section 1 PERIODIC TABLE 45

Development of the Periodic Table Modern Periodic Table Dmitri Mendeleev Lothar Meyer Independently came to the same conclusion about how elements should be grouped 46

Mendeleev and the Periodic Table Chemists mostly credit Mendeleev Organize the table by chemical properties Predicted some missing elements and their expected properties, i.e. germanium 47

Periodic Table Elements are arranged in order of atomic number 48

Periodic Table Representative elements Elements in the same group have similar chemical properties Why? 49

ELECTRON CONFIGURATION 50

Subatomic Particles in an Atom In a neutral atom the number of protons equal the number of electrons (protons and neutrons) Aufbau principle Electrons are added to orbitals as protons are added to an atom 2015 Pearson Education, Inc. 51

Electron Configurations 4p 5 Electron configuration explains how electrons are distributed in an atom Each component consists of a number denoting the energy level (principal quantum number, n) a letter denoting the type of orbital (angular momentum quantum number, l) a superscript denoting the number of electrons in those orbitals The most stable organization is the lowest possible energy, called the ground state 52

How do you determine an atoms electron configuration? 53

Electron Configuration Use the periodic table 54

Electron Configuration Subshell (angular momentum quantum number) s p d f Electron maximum 2 6 10 14 2 columns 6 columns 10 columns 14 columns 55

Electron Configuration Subshell s p d f Electron maximum 2 6 10 14 s p d f 56

Electron Configuration The periodic table can be used to determine subshell (angular momentum quantum number, l) s p d f 57

Electron Configuration All elements located in a group have distinguishing electron in the same subshell s 1 s 2 s 1 s 2 p 1 p 2 p 3 p 4 p 5 p 6 d 1 d 2 d 3 d 4 d 5 d 6 d 7 d 8 d 9 d 10 f 1 f 2 f 3 f 4 f 5 f 6 f 7 f 8 f 9 f 10 f 11 f 12 f 13 f 14 58

Electron Configuration Shell number equals period number 1 2 1s 2s Shell number equals period number minus one 2p 1s 3 4 5 6 7 3s 4s 5s 6s 7s 3d 4d 5d 6d 3p 4p 5p 6p 7p 6 7 4f 5f Shell number equals period number minus two 59

Electron Configurations Hydrogen (Z =1): 1s 1 Helium (Z =2): 1s 2 Lithium (Z =3): 1s 2 2s 1 Beryllium (Z =4): 1s 2 2s 2 Boron (Z =5): 1s 2 2s 2 2p 1 Carbon (Z =6): 1s 2 2s 2 2p 2 Iron (Z =26): 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 6 Mercury (Z =80): 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 6 5s 2 4d 10 5p 6 6s 2 4f 14 5d 10 60

EXAMPLE ELECTRON CONFIGURATIONS Write electron configurations for each element. (a) Mg (a) Magnesium has 12 electrons. Distribute two of these into the 1s orbital, two into the 2s orbital, six into the 2p orbitals, and two into the 3s orbital. SOLUTION Mg 1s 2 2s 2 2p 6 3s 2 You can also write the electron configuration more compactly using the noble gas core notation. For magnesium, use [Ne] to represent 1s 2 2s 2 2p 6. 61

Electron Configurations of Ions Cations: The electrons are lost from the highest energy level (n value) K + is 4s 1 (losing a 4s electron) Al 3+ is 1s 2 2s 2 2p 6 (losing two 3s and 1 3p electrons) Anions: The electron configurations are filled to ns 2 np 6 P 3 is 1s 2 2s 2 2p 6 3s 2 3p 6 (gaining three electrons in 2p) http://images.slideplayer.com/23/6612835/slides/slide_2.jpg 62

EXAMPLE ELECTRON CONFIGURATIONS Continued SKILLBUILDER PLUS Write electron configurations for each ion. (Hint: To determine the number of electrons to include in the electron configuration of an ion, add or subtract electrons as needed to account for the charge of the ion.) (a) Al 3+ (b) Cl Answers: Subtract 1 electron for each unit of positive charge. Add 1 electron for each unit of negative charge. (a) Al 3+ 1s 2 2s 2 2p 6 (b) 63

Electron Configuration The filled inner shell electrons are called core electrons Include completely filled d or f sublevels Electrons in the outer most shell are called valence electrons Elements in the same group of the periodic table have the same number of electrons in the outer most shell 64

EXAMPLE VALENCE ELECTRONS AND CORE ELECTRONS Write an electron configuration for selenium and identify the valence electrons and the core electrons. SOLUTION Write the electron configuration for selenium by determining the total number of electrons from selenium s atomic number (34) and distributing them into the appropriate orbitals. Se 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 10 4p 4 The valence electrons are those in the outermost principal shell. For selenium, the outermost principal shell is the n = 4 shell, which contains 6 electrons (2 in the 4s orbital and 4 in the three 4p orbitals). All other electrons, including those in the 3d orbitals, are core electrons. 65

EXAMPLE VALENCE ELECTRONS AND CORE ELECTRONS Continued SKILLBUILDER Valence Electrons and Core Electrons Write an electron configuration for chlorine and identify the valence electrons and core electrons. Answer: 66

Conceptual Checkpoint Which element has the fewest valence electrons? (a) B (b) Ca (c) O (d) K (e) Ga Answer: 67

Conceptual Checkpoint Below is the electron configuration of calcium: Ca 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 In its reactions, calcium tends to form the Ca 2+ ion. Which electrons are lost upon ionization? (a) the 4s electrons (b) two of the 3p electrons (c) the 3s electrons (d) the 1s electrons Answer: 68

Condensed Electron Configurations Condensed electron configuration Shorthand electron configuration which uses brackets around a noble gas symbol and listing only valence electrons Atom Electron Configuration Condensed Configuration Helium (Z =2) 1s 2 Lithium (Z =3) 1s 2 2s 1 Beryllium (Z =4) 1s 2 2s 2 Boron (Z =5) 1s 2 2s 2 2p 1 Carbon (Z =6) 1s 2 2s 2 2p 2 Oxygen (Z =8) 1s 2 2s 2 2p 4 [He]2s 1 [He]2s 2 [He]2s 2 2p 1 [He]2s 2 2p 2 [He]2s 2 2p 4 2015 Pearson Education, Inc. 69

Condensed Electron Configurations Groups possess the same valence electron configuration 2015 Pearson Education, Inc. 70

EXAMPLE WRITING ELECTRON CONFIGURATIONS FROM THE PERIODIC TABLE Write a condensed electron configuration for arsenic based on its position in the periodic table. SOLUTION The noble gas that precedes arsenic in the periodic table is argon, so the inner electron configuration is [Ar]. Obtain the outer electron configuration by tracing the elements between Ar and As and assigning electrons to the appropriate orbitals. Remember that the highest n value is given by the row number (4 for arsenic). So, begin with [Ar], then add in the two 4s electrons as you trace across the s block, followed by ten 3d electrons as you trace across the d block (the n value for d subshells is equal to the row number minus one), and finally the three 4p electrons as you trace across the p block to As, which is in the third column of the p block: 71

EXAMPLE WRITING ELECTRON CONFIGURATIONS FROM THE PERIODIC TABLE Continued The electron configuration is: As [Ar]4s 2 3d 10 4p 3 SKILLBUILDER Writing Electron Configurations from the Periodic Table Use the periodic table to determine the condensed electron configuration for tin. Answer: 72

Electron configuration specifies subshell occupancy for electrons (angular momentum quantum number, l) What about the magnetic quantum number, m l? 2015 Pearson Education, Inc. 73

ELECTRON ORBITAL DIAGRAMS 74

Electron Orbital Diagrams Magnetic quantum number, m l Determines number of orbitals in each subshell Electron orbital diagram Shows number of electrons in occupied electron orbitals Each box in the diagram represents one orbital Half-arrows represent the electrons Direction of the arrow represents the relative spin of the electron (electron spin quantum number, m s Each orbital only holds 2 electrons 75

Electron Orbital Diagrams: Hund s Rule Hund s rule Every orbital in a subshell is singly occupied before any orbital is doubly occupied All of the electrons in singly occupied orbitals have the same spin Lowest energy attained when the number of electrons with the same spin is maximized For a set of orbitals in the same sublevel, there must be one electron in each orbital before pairing and the electrons have the same spin 76

EXAMPLE WRITING ORBITAL DIAGRAMS Write an orbital diagram for silicon. SOLUTION Since silicon is atomic number 14, it has 14 electrons. Draw a box for each orbital, putting the lowest-energy orbital (1s) on the far left and proceeding to orbitals of higher energy to the right. Distribute the 14 electrons into the orbitals, allowing a maximum of 2 electrons per orbital and remembering Hund s rule. The complete orbital diagram is: 77

Electron Orbital Diagrams Electron configuration specifies subshell occupancy for electrons (angular momentum quantum number, l) Electron orbital diagram specifies orbital occupancy for electrons 78

Electron Configuration Anomalies Some irregularities occur when there are enough electrons to half-fill s and d orbitals on a given row 79

Chromium as an Anomaly Electron configuration for chromium is [Ar] 4s 1 3d 5 rather than the expected [Ar] 4s 2 3d 4 This occurs because the 4s and 3d orbitals are very close in energy These anomalies occur in f-block atoms with f and d orbitals, as well 80

The Periodic Table Final Thoughts 1. Valence electrons that primarily determine an atom s chemistry 2. Electron configurations can be determined from the periodic table 3. Certain groups in the periodic table have special names 4. Basic division of the elements in the periodic table is into metals and nonmetals 81

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What is the shape of a p orbital? A. Spherical B. Doughnut C. Pyramidal D. Dumbbell E. Square 83

How many orbitals are associated with a given set of d orbitals with the same principal quantum number? A. 1 B. 7 C. 3 D. 9 E. 5 84

What is the maximum number of electrons allowed in each f orbital? A. 2 B. 6 C. 8 D. 10 E. 14 85

What is the maximum number of electrons in the n = 4 principal energy level? A. 6 B. 8 C. 18 D. 32 E. 64 86

Which of the following electron configurations is NOT possible? A. 1s 2 2s 2 2p 3 B. [Ar]4s 2 4d 10 4p 4 C. [Ne]3s 2 D. [He]2s 2 2p 6 3s 2 E. [Kr]5s 2 4d 10 5p 2 87

What is the electron configuration for the copper atom? A. 1s 2 2s 2 2p 6 3s 2 3p 6 4s 2 3d 7 B. [Ar]4s 2 4d 9 C. [Ar]4s 1 3d 10 D. 1s 2 2s 2 2p 2 E. [Ar]4s 2 3d 9 88

How many unpaired electrons are in an iron atom? A. 6 B. 20 C. 4 D. 1 E. 0 89

Which of the following atoms has the greatest metallic character? A. Chlorine B. Tellurium (Te) C. Indium (In) D. Carbon E. Aluminum 90

The electron configuration for calcium is 1s 2 2s 2 2p 6 3s 2. Which electrons are lost upon ionization? A. The 3s electrons B. The 2s electrons C. Two of the 2p electrons D. The 1s electrons E. None of the above 91

The lowest energy state of a hydrogen atom is called its state. a. bottom b. ground c. fundamental d. original 92

s orbitals are shaped like a. four-leaf clovers. b. dumbbells. c. spheres. d. triangles. 93

At a node, the probability of finding an electron is %. a. 0 b. 1 c. 50 d. 100 94

What is the maximum number of electrons that can occupy the 5d subshell a. 2 b. 6 c. 10 d. 12 95

Conceptual Checkpoint Which pair of elements has the same total number of electrons in p orbitals? (a) Na and K (b) K and Kr (c) P and N (d) Ar and Ca Answer: 96

Which of the following elements has the following electron configuration 1s 2 2s 2 2p 6 3s 2 3p 5? A. O B. Cl C. F D. Ar E. S 97

What is the electron configuration of the ground state of the P 3 ion? A. [Ar]4s 2 3d 10 4p 1 B. [Ne]3s 2 3p 6 C. [He]2s 2 2p 6 3s 2 D. [Ne]3s 2 3p 3 E. [Ne]3s 2 98

What is the electron configuration for sulfur? A. [Ar]4s 2 4p 5 B. [Ne]3s 2 3p 4 C. 1s 2 2s 2 2p 6 3s 2 3p 4 D. 1s 2 2s 2 2p 6 3s 2 3p 5 E. Two of the above 99

Which of the following ions has the same electron configuration as an argon atom? A. Br B. K + C. S 3 D. P 3+ E. Ca + 100

How many core electrons are in an arsenic (element 33) atom? A. 33 B. 28 C. 18 D. 5 E. 8 101

Which element forms compounds with formulas similar to compounds containing iodine? A. Ar B. S C. Na D. P E. F 102

The electron configuration for bromine is [Ar]4s 2 3d 10 4p 5. List the number of core electrons and valence electrons, respectively. A. 18 and 17 B. 20 and 15 C. 10 and 25 D. 28 and 7 E. 30 and 5 103

The electron configuration of a carbon atom is a. [He]2s 2 2p 6. b. [He]2s 2 2p 4. c. [He]2s 2 2p 2. d. [He]2s 2. 104

The electron configuration of a germanium atom is a. [Ar]4s 2 4p 2. b. [Ar]4s 2 3d 10 4p 2. c. [Kr]4s 2 3d 10 4p 2. d. [Kr]4s 2 3d 10 4p 2. 105

The electron configuration of a copper atom is a. [Ar]4s 2 3d 9. b. [Ar]4s 1 3d 10. c. [Ar]4s 2 3d 10. d. [Ar]4s 2 3d 7. 106

The valence electron configuration of elements in column 6A(16) of the Periodic Table is a. np 6. b. ns 0 np 6. c. ns 2 np 4. d. impossible to predict because each element is unique. 107

Identify the specific element that corresponds to 1s 2 2s 2 2p 6 3s 2 a. Sodium b. Beryllium c. Magnesium d. Calcium 108

Identify the specific element that corresponds to [Kr]5s 2 4d 10 5p 4 a. tin b. antimony c. tellurium d. Iodine 109

The elements located in Group VIIA (Group 17) on the periodic table are called a. alkali metals. b. noble gases. c. chalcogens. d. halogens. 110

Identify the group of elements that corresponds to the generalized electron configuration [noble gas] ns 2 np 5 a. Group 5A b. Group 6A c. Group 7A d. Group 8A 111

Identify the group of elements that corresponds to the generalized electron configuration [noble gas] ns 2 (n-1)d 2 a. Group 3B b. Group 4B c. Group 5B d. Group 6B 112