Chapter 6Chapter 6The Periodic TableThe Periodic Table

Ms. WangMs. Wang

Lawndale High SchoolLawndale High School

Section 6.1 - Organizing the ElementsSection 6.1 - Organizing the Elements

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

By the 1700’s, only about 13 By the 1700’s, only about 13 elements had been identifieselements had been identifies

In 1829, J.W. Dobereiner published a In 1829, J.W. Dobereiner published a classification system with elements classification system with elements grouped into set of three based upon grouped into set of three based upon similar chemical propertiessimilar chemical properties

Mendeleev’s Periodic TableMendeleev’s Periodic Table

From 1829 to 1869, many different From 1829 to 1869, many different systems were proposed, but none systems were proposed, but none gained wide acceptancegained wide acceptance

In 1869, Dmitri Mendeleev arranged In 1869, Dmitri Mendeleev arranged the elements in his periodic table in the elements in his periodic table in order of increasing atomic mass, order of increasing atomic mass, based upon repeating propertiesbased upon repeating properties

The Periodic LawThe Periodic Law

In the modern periodic table, In the modern periodic table, elements are arranged in order of elements are arranged in order of increasing atomic numberincreasing atomic number

Periodic Law – when elements are Periodic Law – when elements are arranged in order of increasing arranged in order of increasing atomic number, there is a periodic atomic number, there is a periodic repetition of their physical and repetition of their physical and chemical propertieschemical properties

Metals, Metalloids and NonmetalsMetals, Metalloids and Nonmetals(Red ladder on the periodic table)(Red ladder on the periodic table)

Elements can be grouped into three Elements can be grouped into three broad classes based on their broad classes based on their general propertiesgeneral properties

MetalsMetalsNonmetalsNonmetalsMetalloidsMetalloids

Metals: elements that are generally Metals: elements that are generally solid at room temperature, have a solid at room temperature, have a grayish color and shiny surface, and grayish color and shiny surface, and conduct heat and electricityconduct heat and electricity

Nonmetals: elements that have Nonmetals: elements that have varying properties but are generally varying properties but are generally poor conductors of heat and electricitypoor conductors of heat and electricity

Metalloids: elements with some Metalloids: elements with some properties of metals and and properties of metals and and nonmetalsnonmetals

Section 6.2 - Classifying the ElementsSection 6.2 - Classifying the Elements(Page 162-163)(Page 162-163)

The periodic table displays the symbols The periodic table displays the symbols and names of the elements, along with and names of the elements, along with information about the structure of their information about the structure of their atomsatoms

Element symbols that are printed in black Element symbols that are printed in black are solid at R.T., blue are liquid at R.T., are solid at R.T., blue are liquid at R.T., and red are gasses at R.T.and red are gasses at R.T.

Some elements are printed in green, which Some elements are printed in green, which means that they are not found in naturemeans that they are not found in nature

1.1. Alkali Metals (Group 1A)Alkali Metals (Group 1A)2.2. Alkaline Earth Metals (Group 2A)Alkaline Earth Metals (Group 2A)3.3. Chalcogens (Group 6A)Chalcogens (Group 6A)4.4. Halogens (Group 7A)Halogens (Group 7A)5.5. Noble Gases (Group 8A)Noble Gases (Group 8A)6.6. Transition Metals (Group B)Transition Metals (Group B)7.7. Inner Transition Metals Inner Transition Metals

(Lanthanides and Actinides)(Lanthanides and Actinides)

The 7 Groups of the Periodic TableThe 7 Groups of the Periodic Table

Electron Configurations in GroupsElectron Configurations in Groups

Elements can be sorted into noble Elements can be sorted into noble gases, representative elements, gases, representative elements, transition metals, or inner transition transition metals, or inner transition meals based on their electron meals based on their electron configurationconfiguration

Noble Gases always have their s and Noble Gases always have their s and p sublevels completely filled with p sublevels completely filled with electrons, which makes them electrons, which makes them relatively inactiverelatively inactive

Representative ElementsRepresentative Elements

Representative Elements are Groups Representative Elements are Groups 1A through 7A because they display 1A through 7A because they display a wide range of physical and a wide range of physical and chemical propertieschemical properties

For any representative element, its For any representative element, its group number always equals the group number always equals the number of electrons in the highest number of electrons in the highest occupied energy level (Valence Shell)occupied energy level (Valence Shell)

Transition MetalsTransition Metals

Transition Metals are characterized Transition Metals are characterized by the presence of electrons in the by the presence of electrons in the dd orbitalorbital

Inner Transition Metals are Inner Transition Metals are characterized by the presence of characterized by the presence of electrons in the electrons in the ff orbital orbital

Section 6.3 – Periodic TrendsSection 6.3 – Periodic Trends

Properties of elements are related to Properties of elements are related to the location of elements in the the location of elements in the periodic tableperiodic table

Four periodic trends:Four periodic trends:–Atomic RadiusAtomic Radius–Ionization EnergyIonization Energy–Electron AffinityElectron Affinity–ElectronegativityElectronegativity

1. Atomic Radius1. Atomic Radius

One-half of the One-half of the distance from distance from center to center center to center of two atoms of of two atoms of the same the same elementelement

Atomic Radius

1. Atomic Radius1. Atomic RadiusWhat do you notice about the atomic radii What do you notice about the atomic radii of the elements on the periodic table? of the elements on the periodic table?

Which element has a greater atomic Which element has a greater atomic radius?radius?– F or CsF or Cs– Ga or KGa or K– Kr or RbKr or Rb

Put these elements in order of Put these elements in order of increasing atomic radiusincreasing atomic radius– Ba, Si, Fr, W, O, AgBa, Si, Fr, W, O, Ag

Atomic Radius Practice

IonsIons

Some compounds are composed of Some compounds are composed of particles called ions.particles called ions.

Ions are atoms that have a positive Ions are atoms that have a positive or negative charge.or negative charge.

Remember that atoms that are Remember that atoms that are electrically neutral have equal electrically neutral have equal number of protons and electronsnumber of protons and electrons

IonsIons

Positive and negative ions form when Positive and negative ions form when electrons are transferred between electrons are transferred between atomsatoms

Cation – an ion with a positive chargeCation – an ion with a positive charge

Anion – an ion with a negative chargeAnion – an ion with a negative charge

2. Ionization Energy2. Ionization Energy

The energy required to remove an The energy required to remove an electron from an atomelectron from an atom

-+

Lithium atom Lithium Ion

2. Ionization Energy2. Ionization Energy

Elements with Elements with low ionization low ionization energy are energy are good good conductors of conductors of electricity electricity

2. Ionization Energy2. Ionization Energy What trend do you notice about the ionization What trend do you notice about the ionization

energy of the elements on the periodic table? energy of the elements on the periodic table?

Which of these elements has a Which of these elements has a greater ionization energy?greater ionization energy?– Ar or KrAr or Kr– Al or NaAl or Na– S or RbS or Rb

Put these elements in order of Put these elements in order of increasing ionization energyincreasing ionization energy– Si, Cs, He, Ca, P, OSi, Cs, He, Ca, P, O

Ionization Energy Practice

Ionic SizeIonic Size

Cations are always smaller than the Cations are always smaller than the atoms from which they formatoms from which they form

Anions are always larger than the Anions are always larger than the atoms from which they formatoms from which they form

WHY? (Hint: think about the electron WHY? (Hint: think about the electron cloud of an atom)cloud of an atom)

Which is larger? Na or NaWhich is larger? Na or Na++, Al or Al, Al or Al3+3+, , I or II or I--, S or S, S or S2-2-

3. Electron Affinity3. Electron Affinity What trend do you notice about the electron What trend do you notice about the electron

affinity of the elements on the periodic table?affinity of the elements on the periodic table?

4. Electronegativity4. Electronegativity The tendency of an atom to attract electrons The tendency of an atom to attract electrons

to itself when in a compoundto itself when in a compound

4. Electronegativity4. ElectronegativityWhat trend do you notice about the electronegativity of What trend do you notice about the electronegativity of

the elements on the periodic table?the elements on the periodic table?

Which element has greater Which element has greater electronegativity?electronegativity?– Na or FNa or F– Ca or CCa or C– Al or MgAl or Mg

Put these elements in order of Put these elements in order of increasing electronegativityincreasing electronegativity– Sr, Al, Ca, K, Cl, F Sr, Al, Ca, K, Cl, F

Electronegativity Practice

HomeworkHomework

Chapter 6 Assessment (Page 181)Chapter 6 Assessment (Page 181)

#’s 26-46, 48, 49, 52, 64#’s 26-46, 48, 49, 52, 64