The Periodic TableThe Periodic Table

Why Do We Use Tables?Why Do We Use Tables?

• We use tables to organize data We use tables to organize data (information)(information)

• Table help us see Table help us see relationships, patterns, and relationships, patterns, and similarities.similarities.

What is the Periodic What is the Periodic Table?Table?

• The periodic tableperiodic table is a table listing all the elements in an organized form.

• The periodic tableperiodic table is organized by the similar characteristicssimilar characteristics of the elements.– Elements are listed in order of order of

increasing atomic numberincreasing atomic number..

What is an Element?What is an Element?

• An element is the simplest form An element is the simplest form of a substance that retains the of a substance that retains the properties and characteristics properties and characteristics of that substance.of that substance.– Examples: Carbon, C; Hydrogen, H, Examples: Carbon, C; Hydrogen, H,

Nitrogen, N; Oxygen, O.Nitrogen, N; Oxygen, O.

Chemical NomenclatureChemical Nomenclature

• In the scientific community, In the scientific community, elements are listed and referred to elements are listed and referred to by using symbols.by using symbols.– First letter of name: First letter of name:

• Hydrogen = HHydrogen = H

– First and second letter of name:First and second letter of name:• Helium = HeHelium = He

– First and third letter of nameFirst and third letter of name• Chlorine = ClChlorine = Cl

– Exceptions = Latin names:Exceptions = Latin names:• Gold = Au (for Auric), Iron = Fe (for Ferric)Gold = Au (for Auric), Iron = Fe (for Ferric)

The First TableThe First Table• Dmitri Mendeleev formed the first Dmitri Mendeleev formed the first

table organizing the elements by table organizing the elements by their atomic mass.their atomic mass.– He also noticed other He also noticed other

similarities among elements:similarities among elements:•DensityDensity•ReactivityReactivity•MaleabilityMaleability

PeriodicPeriodic Patterns Patterns

• MendeleevMendeleev noticed that these noticed that these characteristics repeated in a characteristics repeated in a pattern.pattern.

• Repeating patterns are called Repeating patterns are called periodicperiodic so he named his table so he named his table the the Periodic Table of the Periodic Table of the Elements.Elements.

Mendeleev’s Table

How is the Modern How is the Modern Periodic Table Organized?Periodic Table Organized?• The elements are organized by

increasing atomic number and similar characteristics.

• Elements are similar to other elements found in the same row or column.

Periods, “Rows”Periods, “Rows”

• The properties of elements in the same period, (row across), gradually change as you move from left to right.

Left Right

metals non-metals

Groups, “Families”Groups, “Families”

• Groups, or “families”, are columns that go up and down in the table.

• Elements in the same group, or family, have the same number of electrons in their outer shell.– Elements in the same groupsame group will

combinecombine with other elements in the same waysame way.

Groups with Family Groups with Family NamesNames

• Some groups of the periodic table have “family names” that indicate their similar characteristics.– Alkali Metals– Alkaline Earth Metals– Coinage Metals– Halogens– Inert “Noble” Gases

Alkali Metal FamilyAlkali Metal Family

• The alkali metalsalkali metals, (far left, column 1), are very reactivevery reactive elements because they have only one electron in their outer energy level.– Easy to loose one electron so very reactive.

• Alkali metalsAlkali metals will immediately react with air, water, and other substances in the environment.

• Characteristics: soft (cut w/a knife, have luster, and conduct heat and electricity.

Alkaline Earth Metal Alkaline Earth Metal FamilyFamily

• Alkaline earth metalsAlkaline earth metals, (column 2), are reactive, (but not as reactive as alkali metals), because they have 2 electrons in their outer energy level.– Fairly easy to loose 2 electrons so

fairly reactive.• Characteristics: soft (but harder

than alkali metals), have luster, conduct heat and electricity.

Alkaline Earth Metals

Coinage Metal FamilyCoinage Metal Family

• Contain the metals used to Contain the metals used to make coins. These metals make coins. These metals have various numbers of have various numbers of valence electrons which allows valence electrons which allows the metals to combine with the metals to combine with other metals to form coins.other metals to form coins.– Copper, Cu; Silver, Ag; Gold, Au; Copper, Cu; Silver, Ag; Gold, Au;

Halogen FamilyHalogen Family

• HalogensHalogens, , (group 17, 2(group 17, 2ndnd from right), from right), areare very reactive gasesvery reactive gases that contain 7 that contain 7 electrons in the outer energy level.electrons in the outer energy level.– Easy to gain one electron so very Easy to gain one electron so very

reactive.reactive.

Inert, “Noble”, Gases Inert, “Noble”, Gases FamilyFamily

• The The inert gasesinert gases (group 18, far right) (group 18, far right) have full outer energy levels (8 have full outer energy levels (8 electrons) so they are electrons) so they are non-reactivenon-reactive, , or “inert”.or “inert”.

Inert GasesInert Gases

NeonNeon

ArgonArgon

What is Reactivity?What is Reactivity?

• Reactivity is how easily an element Reactivity is how easily an element will combine with other elements.will combine with other elements.– High reactivity = easier to High reactivity = easier to

combinecombine

• Elements combine with other Elements combine with other elements by gaining, loosing or elements by gaining, loosing or sharing electrons.sharing electrons.

Reactivity of MetalsReactivity of Metals

• MetalsMetals will will loose electronsloose electrons when when they combine with other elements.they combine with other elements.

• The The farther awayfarther away electrons are electrons are from the nucleus the easier they from the nucleus the easier they break away so the break away so the bigger metalsbigger metals have higher reactivity.have higher reactivity.

Reactive MetalsReactive Metals

Reactivity of Non-Reactivity of Non-MetalsMetals

• Non-metalsNon-metals will will gain electronsgain electrons when when combining with other elements.combining with other elements.

• The The closercloser electrons are to the electrons are to the nucleus the stronger the force of nucleus the stronger the force of attraction so the attraction so the smaller the non-smaller the non-metalmetal the the higher the reactivity.higher the reactivity.

Reactive Non-metalsReactive Non-metals

Energy Levels of Energy Levels of ElementsElements

• Energy levels indicate the distance from the nucleus where the electrons are found.– Different energy levels can contain

different amounts of electrons.• K (the first level) can contain 2 electrons• L (the 2nd level) can contain 8 electrons• M (the 3rd level) can contain 18 electrons• N (the 4th level) can contain 32 electrons

Energy of ElectronsEnergy of Electrons

• The closer an electron is to the nucleus, the more energy it takes to separate it from the nucleus.

• The farther away an electron is from the nucleus, the more energy the electron has.

Diagram of Energy Diagram of Energy LevelsLevels

What are Valence What are Valence Electrons?Electrons?

• Valence electrons are the electrons that are found in an elements outer-most energy level.

• Valence electrons are those involved in chemical bonding of elements.

Dot DiagramsDot Diagrams

• A dot diagram is a simple way to show valence electrons and how an element will combine.

• Dot diagrams only show the element and the valence electrons (those electrons that are available for bonding)

Examples of Dot Examples of Dot DiagramsDiagrams

Why Do Elements Why Do Elements Combine?Combine?

• Elements will combine with other elements to become more stable.

• Combining allows elements to fill their outer energy levels.

What is an What is an IonIon??

•An ion is a charged atom.– An atom that has gained or

lost electrons is no longer neutral and now has either a positive “+” or negative “-” electrical charge.

What is an Isotope?What is an Isotope?

• An isotopeisotope is an atom of an element that has the same number of protons, atomic number, as another atom but a different number of neutrons.

ElementsElements, , MixturesMixtures, and , and CompoundsCompounds

• Element = the simplest form of a substance that retains the properties of that substance.

• Mixture = when 2 or more elements are combined in a manner that the properties of each element do not change. In a mixture the original elements can be separated by physical means.

• Compound = a substance formed by the combination of elements in fixed proportions and involving a chemical reaction. In a compound the original elements can not be separated by physical means.

Example of How Elements Example of How Elements of the Same Group Will of the Same Group Will

Combine in the Same WayCombine in the Same Way

What is a Chemical What is a Chemical Formula?Formula?

• Chemical formulas, or molecular formulas, are a shorthand representation of the elements of a substance.

• Chemical formulas tell the exact makeup of a substance.

• Ex. H2O = 2 atoms of Hydrogen and 1 atom of Oxygen.

• C6H12O6 = 6 Carbon, 12 Hydrogen, and 6 Oxygen atoms