Chapter 6 The Periodic Table 6.1 Organizing the Elements

Chapter 6 The Periodic Table 6.1 Organizing the Elements
6.2 Classifying the Elements 6.3 Periodic Trends Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

How can you organize and classify elements?
CHEMISTRY & YOU How can you organize and classify elements? Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Searching for an Organizing Principle
Objectives Discuss how early chemists organized the known elements. Describe how the modern periodic table is organized. Identify three broad classes of elements Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

A few elements, including copper, silver, and gold, have been known for thousands of years. There were only 13 elements identified by the year 1700. Chemists suspected that other elements existed. In one decade (1765–1775), chemists discovered five new elements. As chemists began to use scientific methods to search for elements, the rate of discovery increased. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Early chemists attempted to organize the known elements. Some used the properties of the elements Dobereiner, a German chemist, published a classification system for elements. He organized and grouped the known elements into triads. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Today’s Periodic Table
How is the modern periodic table organized? Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Henry Moseley modified Mendeleev’s table **He arranged the elements by increasing atomic number. **Elements that have similar chemical and physical properties end up in the same column in the periodic table. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

This led to the Periodic Law When the elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

There are seven horizontal rows or periods in the table Each period corresponds to the energy level There are eighteen vertical columns or groups in the table Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Today’s table has 118 elements Many elements have been discovered since his original work The noble gases - due to their unreactivity The lanthanides and actinides series – many are man-made Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Periodicity can be observed in the periodic table *Each group has similar properties The electron configuration tells an element’s position in the periodic table Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Warm-up 1. What is the electron configuration of Phosphorus? 2. Determine the element from the atomic model pictured below. Find the number of valence electrons. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Chapter 6 The Periodic Table 6.2 Classifying the Elements
6.1 Organizing the Elements 6.2 Classifying the Elements 6.3 Periodic Trends Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Electron Configurations in Groups
Objectives Describe the information in a periodic table. Classify elements based on electron configuration. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Blocks of Elements The periodic table is divided into sections, or blocks, that correspond to the highest occupied sublevels. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Electrons play a key role in determining the properties of elements. Elements can be sorted into noble gases, halogens, transition metals, or inner transition metals based on their electron configurations. 1, so there should be a connection between an element’s electron configuration and its location in the periodic table. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Remember: s block – groups 1 & 2 p block – groups 13 – 18 d block – groups 3 – 12 f block – bottom two rows Representative elemdents because they display a wide range of physical and chmiecal properties Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Group 1 – Alkali metals (s1) - Most reactive metals
s block Group 1 – Alkali metals (s1) - Most reactive metals So reactive, not found in nature as elements 1 valence electron Lithium (Li) 1s22s1 Sodium (Na) 1s22s22p63s1 Potassium (K) 1s22s22p63s23p64s1 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Group 2 – Alkaline Earth metals (s2)
s block Group 2 – Alkaline Earth metals (s2) - Less reactive than group 1 metals - 2 valence electrons Beryllium (Be) 1s22s2 Magnesium (Mg) 1s22s22p63s2 Calcium (Ca) 1s22s22p63s23p64s2 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Group 13 – Mixed group (s2p1) - Even less reactive than groups 1 & 2
p block Group 13 – Mixed group (s2p1) - Even less reactive than groups 1 & 2 - 3 valence electrons Boron (B) 1s22s22p1 Aluminum (Al) 1s22s22p63s23p1 Gallium (Ga) 1s22s22p63s23p64s23d104p1 Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Group 14 – Mixed group (s2p2) - 4 valence electrons
p block Group 14 – Mixed group (s2p2) - 4 valence electrons Group 15 – Mixed group (s2p3) - 5 valence electrons Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

p block Group 16 – Nonmetals (s2p4) - 6 valence electrons
Group 17 – Halogens (s2p5) - Most reactive nonmetals Video1 - 7 valence electrons Video2 - Example Fluorine: 1s22s22p5 Group 18 – Noble Gases (s2p6) - 8 valence electrons (with the exception of helium) - Completely unreactive nonmetals Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

The Noble Gases There are eight electrons in the highest occupied energy level. These eight electrons are called valence electrons highest occupied energy level for each element, which is highlighted in yellow. The s and p sublevels are completely filled with electrons—two electrons in the s sublevel and six electrons in the p sublevel Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

d block f block Groups 3 – 12 – Transition metals
- Have usually 2 or 3 valence electrons - Less reactive than groups 1 & 2 - Have the ability to move their electrons from s and d orbitals f block Bottom two rows - Known as the lanthanides and actinides (inner transition metals or rare earth metals) - Have the ability to move their electrons from s and f orbitals Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Analyze Identify the relevant concepts.
Sample Problem 6.1 Analyze Identify the relevant concepts. 1 For all elements, the atomic number is equal to the total number of electrons. For a representative element, the highest occupied energy level is the same as the number of the period in which the element is located. You can tell how many electrons are in this energy level from the group in which the element is located. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Calculate Apply the concepts to this problem.
Sample Problem 6.1 Calculate Apply the concepts to this problem. 2 Use Figure 6.9 to identify where the atom is in the periodic table and the number of electrons in the atom. 1. This element ends in 3s23p2 Ans: Silicon 2. This element ends in 5s24d2 Ans: Zirconium 3. This element ends in 5s25p5 Ans: Iodine Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

A B C D Section 6.1 Assessment
What is a row of elements on the periodic table called? A. octave B. period C. group D. transition A B C D

A B C D Section 6.1 Assessment What is silicon an example of? A. metal
B. non-metal C. inner transition metal D. metalloid A B C D

Key Concepts Elements can be sorted into noble gases, representative elements, transition metals, or inner transition metals based on their electron configurations. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Three broad classes of elements are metals, nonmetals, and metalloids.
The elements can be grouped into one of these three classes based on their general properties. Dividing the elements into groups is not the only way to classify them based on their properties Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Metals, Nonmetals, and Metalloids
Periodic tables are sometimes color-coded to classify types of elements. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Metals The majority of elements are metals Metals have three key properties 1) Shiny or luster 2) Flexible (malleable – hammer into a sheet and ductile – drawn into a wire) 3) Good conductor of energy (electricity and heat) Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Although there are fewer nonmetals, they are more abundant on Earth Nonmetals have three key properties 1) Dull 2) Brittle 3) Poor conductor of heat and electricity I general, nonmetals are poor conductors of heat and electric current. Carbon, in the form of graphite, is an exception to this rule. Solid nonmetals tend to be brittle, meaning that they will shatter if hit with a hammer. Most nonmetals are gases at room temperature, including the main components of air—nitrogen and oxygen. A few are solids, such as sulfur and phosphorus. One nonmetal, bromine, is a dark-red liquid. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

The variation among nonmetals makes it difficult to describe one set of general properties that will apply to all nonmetals. A diamond, which is composed of carbon, is very hard. Some match heads are coated with phosphorus, a brittle solid. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

There is a heavy stair-step line that separates the metals from the nonmetals. Most of the elements that border this line are shaded green. These elements are metalloids. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

A metalloid generally has properties that are similar to those of metals and nonmetals. Their properties can be changed by conditions Silicon is the most famous metalloid -It is responsible for computer chips Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Silicon is also present as the compound silicon dioxide in glass items. Silicon can be cut into wafers and used to make computer chips. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

CHEMISTRY & YOU All of the known elements are listed in the periodic table. What are different ways you could use the periodic table to classify elements? Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

CHEMISTRY & YOU All of the known elements are listed in the periodic table. What are different ways you could use the periodic table to classify elements? You can use the periodic table to classify elements by their atomic weight, by their chemical properties, by their physical properties, or by their electron configuration. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Key Concepts Early chemists used the properties of elements to sort them into groups. Mendeleev arranged the elements in his periodic table in order of increasing atomic mass. In the modern periodic table, elements are arranged in order of increasing atomic number. Three classes of elements are metals, nonmetals, and metalloids. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Glossary Terms periodic law: when the elements are arranged in order of increasing atomic number, there is a periodic repetition of their physical and chemical properties metal: one of a class of elements that are good conductors of heat and electric current; metals tend to be ductile, malleable, and shiny Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Glossary Terms nonmetal: an element that tends to be a poor conductor of heat and electric current; nonmetals generally have properties opposite to those of metals metalloid: an element that tends to have properties that are similar to those of metals and nonmetals Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Do Now ___ ion ___ atomic radius
___ ionization energy ___ electronegativity The ability of an atom to attract electrons when in a compound Atom that has a positive or negative charge one-half the distance between the nuclei of two atoms when atoms are joined The energy required to remove an electron from an atom Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Terrence Howard Wears Diamonds https://www. youtube. com/watch

Chapter 6 The Periodic Table 6.3 Periodic Trends
6.1 Organizing the Elements 6.2 Classifying the Elements 6.3 Periodic Trends Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Objectives Describe trends among elements for atomic size (radii), ionization energy, electron affinity, and electronegativity. Explain how ions form. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

There are several trends in the periodic table
Valence electrons Atomic radii Ionic radii Ionization energy Electron affinity Electronegativity Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Trends in Atomic Size Trends in Atomic Radii The distance between the nuclei of two identical atoms (i.e. two chlorine atoms) that are bonded together can be used to estimate the size of the atoms. Atomic radii is one half the distance between the nuclei of two atoms of the same element What are the trends among the elements for atomic size? One way to think about atomic size is to look at the units that form when atoms of the same element are joined to one another. These units are called molecules. The atoms in each molecule shown below are identical The atomic radius is often measured in picometers (pm). Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Atomic Radius Trend: Down a group – atomic radii increases
Trends in Atomic Size Atomic Radius Trend: Down a group – atomic radii increases -This happens because of the increased number of energy levels -The energy levels shield the electrons from the attraction of protons in the nucleus The increase in positive charge draws electrons closer to the nucleus. The increase in the number of occupied orbitals shields electrons in the highest occupied energy level from the attraction of protons in the nucleus. The shielding effect is greater than the effect of the increase in nuclear charge, so the atomic size increases. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Atomic Radius Trend: Across a period – atomic radii decreases
Trends in Atomic Size Atomic Radius Trend: Across a period – atomic radii decreases -This happens because as more electrons are added to the same energy level, those electrons are pulled closer due to the increased number of protons in the nucleus Largest atomic radii – francium Smallest atomic radii – fluorine The increase in positive charge draws electrons closer to the nucleus. The increase in the number of occupied orbitals shields electrons in the highest occupied energy level from the attraction of protons in the nucleus. The shielding effect is greater than the effect of the increase in nuclear charge, so the atomic size increases. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Periodic Trends in Atomic Size
Across a period, the electrons are added to the same principal energy level. Atomic radius (pm) Atomic number The shielding effect is constant for all elements in a period. The increasing nuclear charge pulls the electrons in the highest occupied energy level closer to the nucleus, and the atomic size decreases. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Group Trends in Atomic Size
Interpret Graphs Group Trends in Atomic Size The atomic radius within these groups increases as the atomic number increases. Atomic radius (pm) Atomic number This increase is an example of a trend. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

What are the trends for atomic radii?
In general, atomic radius increases from top to bottom within a group and decreases from left to right across a period. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

These are the electrons available to be gained, lost, or shared
Trends in Atomic Size Valence electrons are the electrons found in the outermost energy level These are the electrons available to be gained, lost, or shared All atoms want 8 valence electrons or a full outer energy level Noble gas electron configuration Valence electrons determine the chemical properties of the atom Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

All atoms want 8 valence electrons or a full outer energy level
Noble gas electron configuration Valence electrons determine the chemical properties of the atom Valence electrons can be represented using Lewis Dot Diagrams Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Valence electrons can be represented using Lewis Dot Diagrams
Trends in Atomic Size Valence electrons can be represented using Lewis Dot Diagrams Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Do Now What is the trend in atomic radii going down a group?
Explain your answer for #1. What is the trend in atomic radii going left to right across the periodic table? Draw the Lewis Dot Diagram for Boron. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Sometimes atoms can gain or lose electrons to form ions
Atoms are neutral because there are equal numbers of both protons and electrons Example: Sodium (Na) 11 positively charged protons negatively charged electrons The net charge on a sodium atom is zero [(+11) + (-11) = 0]. Sometimes atoms can gain or lose electrons to form ions Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Losing electrons results in a positive ion called a cation
An ion is an atom or group of atoms that has a positive or negative charge Losing electrons results in a positive ion called a cation Gaining electrons results in a negative ion called an anion Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Metals (left side of the table) form cations
Cations are smaller than their atom counterparts because they are losing an electron (and sometimes an energy level) More positive charges have a greater pull on less negative charges Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Nonmetals (right side of the table) form anions
Anions are larger than their atom counterparts because they are gaining an electron Less positive charges cannot pull in the greater number of negative charges Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Nonmetals tend to form anions. Metals tend to form cations.
What type of element tends to form anions? What type tends to form cations? Nonmetals tend to form anions. Metals tend to form cations. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Ionization Energy video
Ionization energy is the energy required to remove an electron from an atom a low IE means it is easier to remove the electron Atoms can lose an electron, to form an ion They do this to achieve noble gas electron configuration (or 8 valence electrons) When an atom easily loses electrons, it is said to be active Metals tend to lose electrons Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Ionization Energy Down a group – ionization energy decreases
As the valence electrons are farther from the nucleus, the atom gives them up easily, requiring little energy to remove them Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Ionization Energy Across a period – ionization energy increases
As the number of valence electrons increases in the same energy level, the atom is more resistant to giving up an electron (more energy) Greatest IE – fluorine Least IE - francium Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Electronegativity Electronegativity is the measure of the ability of an atom in a chemical compound to attract electrons All values are based on fluorine - Fluorine is most electronegative atom - 4.0 - The trend decreases in either direction from fluorine Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Electronegativity Values for Selected Elements
Interpret Data This table lists electronegativity values for representative elements in Groups 1A through 7A. Electronegativity Values for Selected Elements H 2.1 Li 1.0 Be 1.5 B 2.0 C 2.5 N 3.0 O 3.5 F 4.0 Na 0.9 Mg 1.2 Al Si 1.8 P S Cl K 0.8 Ca Ga 1.6 Ge As Se 2.4 Br 2.8 Rb Sr In 1.7 Sn Sb 1.9 Te I Cs 0.7 Ba Tl Pb Bi The data in this table is expressed in Pauling units. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Electronegativity Trend

Key Concepts In general, atomic size increases from top to bottom within a group and decreases from left to right across a period. Positive and negative ions form when electrons are transferred between atoms. First ionization energy tends to decrease from top to bottom within a group and decrease from left to right across a period. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Key Concepts In general, electronegativity values decrease from top to bottom within a group. For representative elements, the values tend to increase from left to right across a period. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Atoms are neutral because there are equal numbers of both protons and electrons
Ex. Carbon C protons 6 electrons Sometimes atoms can gain or lose electrons to form ions An ion is an atom or group of atoms that has a positive or negative charge Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Losing electrons results in a positive ion called a cation
Metals (left side of the table) form cations Example: K1+ Gaining electrons results in a negative ion called an anion Nonmetals (right side of the table) form anions Example: Cl1- Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Practice Lithium Li # ___ protons # ___ electrons Li1+ # ___ protons
Oxygen O # ___ protons O # ___ protons

Electrons and the Structure of Atoms
BIG IDEA Electrons and the Structure of Atoms Periodic tables may contain each element’s name, symbol, atomic number, atomic mass, and number of electrons in each energy level. The electron configuration of an element can be determined based on the location of an element in the periodic table. Copyright © Pearson Education, Inc., or its affiliates. All Rights Reserved. .

Chapter 6 The Periodic Table 6.1 Organizing the Elements

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