The Periodic The Periodic Table of the Table of the

ElementsElements

Basic OrganizationBasic Organization Atomic structure is used to organize the Atomic structure is used to organize the

elements in the periodic table.elements in the periodic table. Organized by atomic numberOrganized by atomic number The periodic table is useful in predicting The periodic table is useful in predicting

the chemical behavior, trends, and the the chemical behavior, trends, and the properties on the elements.properties on the elements.

3 basic categories:3 basic categories:MetalsMetalsNonmetalsNonmetalsMetalloidsMetalloids

Atomic Structure ReviewAtomic Structure ReviewAtoms are made of Atoms are made of protonsprotons,,

electronselectrons,, andand neutrons.neutrons.

ElementsElements are are atoms atoms of only one of only one type.type.

ElementsElements are identified by the are identified by the atomic numberatomic number (# of protons in (# of protons in nucleus).nucleus).

Energy Levels ReviewEnergy Levels ReviewElectronsElectrons are arranged in regions are arranged in regions

around the nucleus called around the nucleus called energy energy levels.levels.

At least 1 energy level and as many At least 1 energy level and as many as 7 levels exist in atoms.as 7 levels exist in atoms.

Electrons in levels farther away from Electrons in levels farther away from the nucleus have more energy.the nucleus have more energy.

Inner levels will fill first before outer Inner levels will fill first before outer levels.levels.

Energy Levels & Valence Energy Levels & Valence ElectronsElectrons

Energy levels hold a specific amount Energy levels hold a specific amount of electrons:of electrons: 11stst level = up to 2, level = up to 2, 22ndnd level = up to 8 level = up to 8 33rdrd level = up to18 level = up to18

The electrons in the outermost level The electrons in the outermost level are called are called valence electrons.valence electrons. Determine how elements will react with othersDetermine how elements will react with others Outermost level does not usually fill completely Outermost level does not usually fill completely

with electrons.with electrons.

Using the Table to Identify Using the Table to Identify Valence ElectronsValence Electrons

Elements are grouped because they Elements are grouped because they have similar properties. have similar properties.

Group numbers can help you Group numbers can help you determine the number of valence determine the number of valence electrons:electrons:Group 1 has 1 valence electron.Group 1 has 1 valence electron.Group 2 has 2 valence electrons.Group 2 has 2 valence electrons.Groups 3 – 12 are transition metals and Groups 3 – 12 are transition metals and

have 1 or 2 valence electrons.have 1 or 2 valence electrons.

Using the Table to Identify Using the Table to Identify Valence Electrons cont.Valence Electrons cont.

Groups 13 – 18 have 10 fewer than Groups 13 – 18 have 10 fewer than the group number. For example:the group number. For example:group 13 has 3 valence electronsgroup 13 has 3 valence electronsgroup 15 has 5 valence electronsgroup 15 has 5 valence electronsgroup 18 has 8 valence electronsgroup 18 has 8 valence electrons

Grouping the ElementsGrouping the Elements

The most reactive metals are the The most reactive metals are the elements in Group 1 and 2. elements in Group 1 and 2.

What makes an element reactive?What makes an element reactive?● Number of valence electrons each atom Number of valence electrons each atom

hashas● When outer levels are full, atoms are When outer levels are full, atoms are

stablestable● When they are not full, they react: gain, When they are not full, they react: gain,

lose, or share 1 or 2 electronslose, or share 1 or 2 electrons

Groups Groups Groups run vertically in the periodic Groups run vertically in the periodic

table. table. They are numbered from 1 – 18.They are numbered from 1 – 18.Elements in the same groups have Elements in the same groups have

the same number of electrons in the the same number of electrons in the outer energy level.outer energy level.

Grouped elements behave Grouped elements behave chemically in similar ways.chemically in similar ways.

Group 1: Alkali MetalsGroup 1: Alkali MetalsContains: MetalsContains: MetalsValence Electrons: 1Valence Electrons: 1Reactivity: Very ReactiveReactivity: Very ReactiveProperties: Properties:

solidssolidssoftsoftreact violently with waterreact violently with watershiny shiny low densitylow density

Group 2: Alkaline-Earth Group 2: Alkaline-Earth MetalsMetals

Contains: MetalsContains: MetalsValence Electrons: 2Valence Electrons: 2Reactivity: very reactive but less Reactivity: very reactive but less

reactive than alkali metals (Group 1)reactive than alkali metals (Group 1)Properties: Properties:

SolidsSolidsSilver coloredSilver coloredMore dense than alkali metalsMore dense than alkali metals

Groups 3-12 Transition Groups 3-12 Transition MetalsMetals

Contain: MetalsContain: MetalsValence electrons: 1 or 2Valence electrons: 1 or 2Reactivity: less reactive than alkali Reactivity: less reactive than alkali

and alkaline-earth metalsand alkaline-earth metalsProperties:Properties:

Higher densityHigher densityGood conductors of heat and electricityGood conductors of heat and electricity

Groups 3-12 Transition MetalsGroups 3-12 Transition MetalsBelow Main TableBelow Main Table

Contain: The Lanthanide and Actinide Contain: The Lanthanide and Actinide SeriesSeriesThese two rows are pulled out of These two rows are pulled out of

sequence and placed below the main sequence and placed below the main table to keep the table from being too table to keep the table from being too wide.wide.

Lanthanides are #’s 58 – 71.Lanthanides are #’s 58 – 71.Actinides are #’s 90 – 103.Actinides are #’s 90 – 103.

Groups 3-12 Rare Earth Groups 3-12 Rare Earth Elements ~ LanthanidesElements ~ Lanthanides

Lanthanides follow the transition Lanthanides follow the transition metal # 57 Lanthanum in Period 6.metal # 57 Lanthanum in Period 6.

Valence electrons: 3Valence electrons: 3Reactivity: Very reactiveReactivity: Very reactiveProperties:Properties:

● High luster but tarnish easily High luster but tarnish easily ● High conductivity for electricityHigh conductivity for electricity● Very small differences between themVery small differences between them

Groups 3-12 Rare Earth Groups 3-12 Rare Earth Elements ~ ActinidesElements ~ Actinides

Actinides follow the transition metal Actinides follow the transition metal # 89 Actinium in Period 7# 89 Actinium in Period 7

Valence electrons: 3 (but up to 6)Valence electrons: 3 (but up to 6)Reactivity: unstableReactivity: unstable

All are radioactiveAll are radioactiveMost made in laboratoriesMost made in laboratories

Metalloids Metalloids A zig-zag line that separates metals A zig-zag line that separates metals

from metalloidsfrom metalloidsElements from Groups 13 – 17 Elements from Groups 13 – 17

contain some metalloids.contain some metalloids.

These elements have characteristics These elements have characteristics of metals and nonmetals.of metals and nonmetals.

Group 13: Boron GroupGroup 13: Boron Group

Group 13: Boron GroupGroup 13: Boron GroupContains: 1 metalloid and 4 metalsContains: 1 metalloid and 4 metalsValence Electrons: 3Valence Electrons: 3Reactivity: ReactiveReactivity: ReactiveOther shared properties:Other shared properties:

Solid at room temperatureSolid at room temperature

Group 14: Carbon GroupGroup 14: Carbon Group

Contains: 1 non-metal, 2 metalloids, Contains: 1 non-metal, 2 metalloids, and 3 metalsand 3 metals

Valence Electrons: 4Valence Electrons: 4Reactivity: VariesReactivity: VariesOther shared properties: Other shared properties:

Solid at room temperatureSolid at room temperature

Group 15: Nitrogen GroupGroup 15: Nitrogen Group

Contains: 2 non-metals, 2 metalloids, Contains: 2 non-metals, 2 metalloids, and 1 metaland 1 metal

Valence electrons: 5Valence electrons: 5Reactivity: VariesReactivity: VariesOther shared properties: Other shared properties:

All but N are solid at room temperature All but N are solid at room temperature

Group 16: Oxygen GroupGroup 16: Oxygen Group

Contains: 3 non-metals, 1 metalloid, Contains: 3 non-metals, 1 metalloid, and 2 metalsand 2 metals

Valence Electrons: 6Valence Electrons: 6Reactivity: ReactiveReactivity: ReactiveOther shared properties: Other shared properties:

All but O are solid at room temperature. All but O are solid at room temperature.

Groups 17 : HalogensGroups 17 : Halogens

Contain: NonmetalsContain: NonmetalsValence Electrons: 7Valence Electrons: 7Reactivity: Very reactiveReactivity: Very reactiveOther shared propertiesOther shared properties

● Poor conductors of electric currentPoor conductors of electric current● React violently with alkali metals to form React violently with alkali metals to form

saltssalts● Never found uncombined in natureNever found uncombined in nature

Group 18 Noble GasesGroup 18 Noble Gases

Contains: NonmetalsContains: NonmetalsValence Electrons: 8 (2 for He)Valence Electrons: 8 (2 for He)Reactivity: Unreactive (least reactive Reactivity: Unreactive (least reactive

group)group)Other shared properties: Other shared properties:

Colorless, odorless gases at room Colorless, odorless gases at room temperaturetemperature

Outermost energy level fullOutermost energy level fullAll found in atmosphereAll found in atmosphere

Hydrogen Stands ApartHydrogen Stands Apart

H set apart because its properties H set apart because its properties don’t match any single group.don’t match any single group.

Valence electrons: 1Valence electrons: 1Reactivity: very but loses the 1 Reactivity: very but loses the 1

electron easilyelectron easilyProperties:Properties:

Similar to those of non-metals rather Similar to those of non-metals rather than metals than metals

PeriodsPeriods Periods run horizontally across the Periods run horizontally across the

Periodic TablePeriodic Table Periods are numbered 1 Periods are numbered 1 –– 7 7 All the elements in a period will have the All the elements in a period will have the

same number of energy levels, which same number of energy levels, which contain electrons. Examples:contain electrons. Examples:

Period 1 atoms have 1 energy level.Period 1 atoms have 1 energy level.Period 2 atoms have 2 energy levels.Period 2 atoms have 2 energy levels.Period 5 atoms have 5 energy levels.Period 5 atoms have 5 energy levels.

Periods continuedPeriods continuedMoving across from left to right across Moving across from left to right across

a period, each element has one more a period, each element has one more electron in the outer shell of its atom electron in the outer shell of its atom than the element before it. than the element before it.

This leads to a fairly regular pattern of This leads to a fairly regular pattern of change in the chemical behavior of the change in the chemical behavior of the elements across a period.elements across a period.