Chapter 6: The Periodic Table 6.1 Organizing the Elements

Chapter 6: The Periodic Chapter 6: The Periodic TableTable

6.1 Organizing the 6.1 Organizing the ElementsElements

Searching For an Organizing Searching For an Organizing PrinciplePrinciple

Chemists used the properties Chemists used the properties of elements to sort them into of elements to sort them into groups.groups.

Mendeleev’s Periodic TableMendeleev’s Periodic Table

Mendeleev arranged the Mendeleev arranged the elements in his periodic table in elements in his periodic table in order of increasing atomic mass.order of increasing atomic mass.

The periodic table can be The periodic table can be used to predict the properties used to predict the properties of undiscovered elements.of undiscovered elements.

6.1

MendeleevMendeleevPredicted properties of Predicted properties of

undiscovered elements.undiscovered elements.

MoseleyMoseley Henry Mosely Henry Mosely (1913, (1913,

British)British)

Organized elements by Organized elements by increasing increasing atomic atomic numbernumber..

Resolved discrepancies Resolved discrepancies in Mendeleev’s in Mendeleev’s arrangement.arrangement.

The Periodic LawThe Periodic LawIn the modern periodic table, In the modern periodic table, elements are arranged in elements are arranged in order of increasing atomic order of increasing atomic number.number.

6.1

The Periodic LawThe Periodic Law The The periodic law:periodic law: When elements are When elements are

arranged in order of increasing atomic arranged in order of increasing atomic number, there is a periodic repetition of number, there is a periodic repetition of their physical and chemical properties.their physical and chemical properties. The properties of the elements within a The properties of the elements within a

period change as you move across a period change as you move across a period from left to right.period from left to right.

The pattern of properties within a period The pattern of properties within a period repeats as you move from one period to repeats as you move from one period to the next.the next.

6.1

Metals, Nonmetals, and Metals, Nonmetals, and MetalloidsMetalloids

Three classes of elements are Three classes of elements are metals, nonmetals, and metals, nonmetals, and metalloids.metalloids.

Across a period, the Across a period, the properties of elements properties of elements become less metallic and become less metallic and more nonmetallic.more nonmetallic.

6.1


MetalsMetalsMetalsMetals are good conductors of are good conductors of heat and electric current.heat and electric current.80% of elements are metals.80% of elements are metals.Metals have a high luster, are Metals have a high luster, are ductile, and are malleable.ductile, and are malleable.

6.1

NonmetalsNonmetals In general, In general, nonmetalsnonmetals are poor are poor

conductors of heat and electric current.conductors of heat and electric current.Most nonmetals are gases at room Most nonmetals are gases at room temperature.temperature.

A few nonmetals are solids, such as A few nonmetals are solids, such as sulfur and phosphorus.sulfur and phosphorus.

One nonmetal, bromine, is a dark-One nonmetal, bromine, is a dark-red liquid.red liquid.


MetalloidsMetalloidsA A metalloidmetalloid generally has generally has properties that are similar to properties that are similar to those of metals and nonmetals.those of metals and nonmetals.

The behavior of a metalloid The behavior of a metalloid can be controlled by changing can be controlled by changing conditions.conditions.

6.1

1.1. The modern periodic table The modern periodic table has elements arranged in order ofhas elements arranged in order of

a) colors.a) colors.

b) melting and boiling points.b) melting and boiling points.

c) increasing atomic mass.c) increasing atomic mass.

d) increasing atomic number.d) increasing atomic number.

6.1 Section Quiz6.1 Section Quiz

2. 2. Mendeleev arranged the Mendeleev arranged the elements in his periodic table in elements in his periodic table in order of increasingorder of increasing

a) atomic number.a) atomic number.

b) number of protons.b) number of protons.

c) number of electrons.c) number of electrons.

d) atomic massd) atomic mass


3. 3. Which one of the following is Which one of the following is NOT a general property of metals?NOT a general property of metals?

a) ductilitya) ductility

b) malleabilityb) malleability

c) having a high lusterc) having a high luster

d) poor conductor of heat and d) poor conductor of heat and electricityelectricity


6.2 Classifying the 6.2 Classifying the ElementsElements

Squares in the Periodic TableSquares in the Periodic TableThe periodic table displays the The periodic table displays the

symbols and names of the symbols and names of the elements, along with information elements, along with information about the structure of their atoms.about the structure of their atoms.

6.2

Squares in the Periodic TableSquares in the Periodic Table The background colors in the squares are The background colors in the squares are

used to distinguish groups of elements.used to distinguish groups of elements.The Group 1A elements are called The Group 1A elements are called alkali alkali

metals.metals.The Group 2A elements are called The Group 2A elements are called

alkaline earth metals.alkaline earth metals.The nonmetals of Group 7A are called The nonmetals of Group 7A are called

halogens.halogens.

6.2

The Noble Gases - NonreactiveThe Noble Gases - NonreactiveThe The noble gasesnoble gases are the elements are the elements

in Group 8A of the periodic table. in Group 8A of the periodic table. The electron configurations for the The electron configurations for the first four noble gases in Group 8A first four noble gases in Group 8A are listed below.are listed below.

The Representative ElementsThe Representative Elements Elements in groups 1A through 7A are often Elements in groups 1A through 7A are often

referred to as referred to as representative elementsrepresentative elements because they display a wide range of because they display a wide range of physical and chemical properties. physical and chemical properties.

The The ss and and pp sublevels of the highest sublevels of the highest occupied energy level are not filled.occupied energy level are not filled.

The group number equals the number of The group number equals the number of electrons in the highest occupied energy electrons in the highest occupied energy level.level.

6.2

Transition ElementsTransition Elements

Transition ElementsTransition ElementsThere are two types of There are two types of transition elements—transition transition elements—transition metals and inner transition metals and inner transition metals. They are classified metals. They are classified based on their electron based on their electron configurations.configurations.

6.2

Transition ElementsTransition ElementsIn atoms of a In atoms of a transition metaltransition metal, , the highest occupied the highest occupied ss sublevel sublevel and a nearby and a nearby dd sublevel contain sublevel contain electrons. electrons.

In atoms of an In atoms of an inner transition inner transition metalmetal, the highest occupied , the highest occupied ss sublevel and a nearby sublevel and a nearby ff sublevel sublevel generally contain electrons.generally contain electrons.

6.2

Full energy levelFull energy level

1

2

3

4 5

6

7

Full sublevel (s, p, d, f)Full sublevel (s, p, d, f) Half-full sublevelHalf-full sublevel

StabilityStability

Write configurations for:Write configurations for:

1) sulfur1) sulfur2) gallium2) gallium3) hafnium3) hafnium4) radium4) radium5) fluorine5) fluorine6) silicon6) silicon

7) cesium7) cesium8) lead8) lead9) iodine9) iodine10) bromine10) bromine11) tin11) tin12) polonium12) polonium

Which element is:Which element is:

1) [Kr]5s1) [Kr]5s224d4d10105p5p11

2) [Xe]6s2) [Xe]6s22

3) [Ne]3s3) [Ne]3s223p3p66

4) [Kr]5s4) [Kr]5s11

5) [Ar]4s5) [Ar]4s223d3d22

Elements HandbookElements Handbook Noble GasesNoble Gases

Look at the atomic properties of Look at the atomic properties of noble gases on page R36. Use what noble gases on page R36. Use what you know about the structure of you know about the structure of atoms to explain why the color atoms to explain why the color produced in a gas discharge tube is produced in a gas discharge tube is different for each gas.different for each gas.

Read p.168: True ColorsRead p.168: True Colors

6.2 Section Quiz6.2 Section Quiz1. Which of the following information 1. Which of the following information

about elements is usually NOT about elements is usually NOT included in a periodic table?included in a periodic table?

a)a) colorcolor

b)b) symbolsymbol

c)c) atomic numberatomic number

d)d) atomic massatomic mass

6.2 Section Quiz6.2 Section Quiz2. An alkali metal would have in 2. An alkali metal would have in

the highest occupied energy levelthe highest occupied energy level

a) a) an an ss22 electron. electron.

b)b) an an ss11 electron. electron.

c)c) pp22 electrons.electrons.

d)d) pp66 electrons. electrons.

3. Which one of the following is 3. Which one of the following is incorrectly labeled? incorrectly labeled?

a) Ne, noble gasa) Ne, noble gas

b) Cu, transition metalb) Cu, transition metal

c) Ga, transition metalc) Ga, transition metal

d) Cl, halogend) Cl, halogen


6.2 Section Quiz6.2 Section Quiz4. Transition metals are characterized as 4. Transition metals are characterized as

being different than representative being different than representative elements because they have electrons in elements because they have electrons in which orbitals? which orbitals? a) a) ppb) b) ddc) c) ssd) d) ff

6.3 Periodic Trends6.3 Periodic Trends

ReactivityReactivity

Most reactive metals are at the Most reactive metals are at the bottom of the groups (Fr)bottom of the groups (Fr)

Most reactive nonmetals are at Most reactive nonmetals are at the top of the groups (F)the top of the groups (F)

Trends in Atomic SizeTrends in Atomic Size The The atomic radiusatomic radius is one half of the is one half of the

distance between the nuclei of two distance between the nuclei of two atoms of the same element when atoms of the same element when the atoms are joined.the atoms are joined.

6.3

Trends in Atomic SizeTrends in Atomic Size

In general, atomic size increases In general, atomic size increases from top to bottom within a group from top to bottom within a group and decreases from left to right and decreases from left to right across a period.across a period. Increased nuclear chargeIncreased nuclear chargeShielding effectShielding effect

6.3

Atomic RadiiAtomic Radii

Which has the largest atomic Which has the largest atomic radius: carbon, fluorine, beryllium radius: carbon, fluorine, beryllium or lithium?or lithium?

Which has the largest atomic Which has the largest atomic radius: magnesium, silicon, sulfur radius: magnesium, silicon, sulfur or sodium? The smallest?or sodium? The smallest?

Positive and negative ions Positive and negative ions form when electrons are form when electrons are transferred between atoms.transferred between atoms.

6.3

IonsIons Some compounds are composed of Some compounds are composed of

particles called ions.particles called ions.An An ionion is an atom or group of atoms that is an atom or group of atoms that

has a positive or negative charge.has a positive or negative charge.A A cationcation is an ion with a positive charge. is an ion with a positive charge. An An anionanion is an ion with a negative charge. is an ion with a negative charge.

6.3

Trends in Ionization EnergyTrends in Ionization Energy

The energy required to remove an The energy required to remove an electron from an atom is called electron from an atom is called ionization energyionization energy..The energy required to remove The energy required to remove

the first electron from an atom is the first electron from an atom is called the first ionization energy. called the first ionization energy.

6.3

Trends in Ionization EnergyTrends in Ionization Energy

Group and Periodic Trends in Group and Periodic Trends in Ionization EnergyIonization EnergyFirst ionization energy tends to First ionization energy tends to

decrease from top to bottom decrease from top to bottom within a group and increase within a group and increase from left to right across a period.from left to right across a period.

6.3

Ionization EnergyIonization Energy

Choose the element with the Choose the element with the higher first ionization energy:higher first ionization energy:Ca and BaCa and BaCa and BrCa and BrCa and KCa and KCa and MgCa and Mg

Ionization EnergyIonization Energy Consider two main-group elements, A Consider two main-group elements, A

and B. Element A has a first and B. Element A has a first ionization energy of 419 kJ/mol. ionization energy of 419 kJ/mol. Element B has a first ionization Element B has a first ionization energy of 1000 kJ/mol. Decide if energy of 1000 kJ/mol. Decide if each element is more likely to be in each element is more likely to be in the the ss block or block or pp block. Which element block. Which element is more likely to form a positive ion?is more likely to form a positive ion?

Q: 3sQ: 3s223p3p55 R: 3sR: 3s11

T: 5sT: 5s224d4d10105p5p55 X: 5sX: 5s224d4d10105p5p11

Identify the block location of each hypothetical Identify the block location of each hypothetical elementelement

Which elements are in the same period? In Which elements are in the same period? In the same group?the same group?

Which element would have the highest first Which element would have the highest first ionization energy? The lowest?ionization energy? The lowest?

Which element would have the highest second Which element would have the highest second ionization energy?ionization energy?

Which element is most likely to form a 1+ ion?Which element is most likely to form a 1+ ion?

Ionization EnergyIonization Energy

A period 3 representative element A period 3 representative element is part of the rough material on is part of the rough material on the side of a match box. Us the the side of a match box. Us the information in the table to identify information in the table to identify the element.the element.

Number 1st 2nd 3rd 4th 5th 6th

Ionization Energy

1010 1905 2910 4957 6265 21,238

Electron AffinityElectron Affinity

Electron affinityElectron affinity – energy change – energy change that occurs when an electron is that occurs when an electron is acquired by a neutral atomacquired by a neutral atom In general it becomes more In general it becomes more

negative across the p block negative across the p block (halogen’s have large electron (halogen’s have large electron affinities)affinities)

Trends in Ionic SizeTrends in Ionic Size

Trends in Ionic SizeTrends in Ionic SizeDuring reactions between metals During reactions between metals

and nonmetals, metal atoms tend and nonmetals, metal atoms tend to lose electrons, and nonmetal to lose electrons, and nonmetal atoms tend to gain electrons. The atoms tend to gain electrons. The transfer has a predictable effect transfer has a predictable effect on the size of the ions that form.on the size of the ions that form.

6.3

Trends in Ionic SizeTrends in Ionic Size

Cations are always Cations are always smaller than the atoms smaller than the atoms from which they form. from which they form. Anions are always larger Anions are always larger than the atoms from than the atoms from which they form.which they form.

6.3

Trends in ElectronegativityTrends in Electronegativity ElectronegativityElectronegativity is the ability of an is the ability of an

atom of an element to attract electrons atom of an element to attract electrons when the atom is in a compound.when the atom is in a compound. In general, electronegativity values In general, electronegativity values

decrease from top to bottom within a decrease from top to bottom within a group. For representative elements, group. For representative elements, the values tend to increase from left the values tend to increase from left to right across a period.to right across a period.

6.3

ElectronegativityElectronegativity

Of gallium, bromine and calcium, Of gallium, bromine and calcium, which has the highest which has the highest electronegativity?electronegativity?

E=2sE=2s222p2p55 G=5sG=5s224d4d10105p5p55 J=2sJ=2s222p2p22

L=6sL=6s225d5d10106p6p55 M=2sM=2s222p2p44

Identify the block location for each element. Which Identify the block location for each element. Which elements are in the same period and which are in elements are in the same period and which are in the same group?the same group?

Which would have the highest electron affinity? Which would have the highest electron affinity? Which would form a 1- ion? Which would have the Which would form a 1- ion? Which would have the highest electronegativity?highest electronegativity?

Compare the ionic radius of the typical ion formed Compare the ionic radius of the typical ion formed by element G with the radius of the atom from which by element G with the radius of the atom from which the ion was formed.the ion was formed.

Which contain seven valence electrons?Which contain seven valence electrons?

Summary of TrendsSummary of Trends

The trends that exist The trends that exist among these properties among these properties can be explained by can be explained by variations in atomic variations in atomic structure.structure.

6.3

Writing ActivityWriting Activity Explaining Trends in Atomic SizeExplaining Trends in Atomic Size

Explain why the size of an atom Explain why the size of an atom tends to increase from top to tends to increase from top to bottom within a group. Explain bottom within a group. Explain why the size of an atom tends to why the size of an atom tends to decrease from left to right across decrease from left to right across a period.a period.

1. 1. Which of the following Which of the following sequences is correct for atomic sequences is correct for atomic size?size?

a) Mg > Al > Sa) Mg > Al > S

b) Li > Na > Kb) Li > Na > K

c) F > N > Bc) F > N > B

d) F > Cl > Brd) F > Cl > Br


6.3 Section Quiz6.3 Section Quiz2. 2. Metals tend toMetals tend to

a) gain electrons to form cations.a) gain electrons to form cations.

b) gain electrons to form anions.b) gain electrons to form anions.

c) lose electrons to form anions.c) lose electrons to form anions.

d) lose electrons to form cations.d) lose electrons to form cations.

6.3 Section Quiz6.3 Section Quiz3. 3. Which of the following is the Which of the following is the

most electronegative?most electronegative?

a) Cla) Cl

b) Seb) Se

c) Nac) Na

d) Id) I

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Chapter 6: The Periodic Table 6.1 Organizing the Elements