Chapter 5Chapter 5

The periodic tableThe periodic table

Our periodic table is arranged by Our periodic table is arranged by order of increasing atomic number.order of increasing atomic number.

This is called the periodic lawThis is called the periodic law

ArrangementsArrangementsThe rows that go ACROSS the table The rows that go ACROSS the table are called periods.are called periods.

Look all the elements in periods 2 do Look all the elements in periods 2 do they have anything is common?they have anything is common?

What about all the elements in What about all the elements in period 3?period 3?

All elements in the same period have All elements in the same period have the same number of electron levels!the same number of electron levels!

Period 1 all has 1 electron levelPeriod 1 all has 1 electron levelPeriod 2 all has 2 electron levelsPeriod 2 all has 2 electron levelsPeriod 3 all has 3 electron levelsPeriod 3 all has 3 electron levelsPeriod 4 all has 4 electron levelsPeriod 4 all has 4 electron levels

Look at all the elements in period Look at all the elements in period 3….3….

What do you see do they all have What do you see do they all have different?different?

All elements in the period increase All elements in the period increase by 1 proton (Atomic number) as we by 1 proton (Atomic number) as we go across.go across.

They also gain 1 electron as we go They also gain 1 electron as we go across.across.

GroupsGroupsThe rows that go up and down are The rows that go up and down are called groups (or families).called groups (or families).

Look at all the elements in group 2 Look at all the elements in group 2 what do they all have in common?what do they all have in common?

GroupsGroups(almost) All elements in the same (almost) All elements in the same group have the same number of group have the same number of valence electrons.valence electrons.

And since the number of valence And since the number of valence electrons determines the way an electrons determines the way an element reacts, atoms in the same element reacts, atoms in the same group react the same way!!!!group react the same way!!!!

Types of elementsTypes of elementsThere are 3 different types of There are 3 different types of elements elements Metals, Non metals and metalloids Metals, Non metals and metalloids (in between)(in between)

MetalsMetalsMetals are solid at room temperature Metals are solid at room temperature (except mercury Hg)(except mercury Hg)Metals are malleable- they can be Metals are malleable- they can be bent into shapes.bent into shapes.Metals have luster (they are shiny)Metals have luster (they are shiny)They are good conducters of heat They are good conducters of heat and electricity.and electricity.

metalsmetalsMetals lose electrons easily (more on Metals lose electrons easily (more on this later) and they have low electro this later) and they have low electro negativity. negativity.

NonmetalsNonmetalsMost nonmetals are either gas or Most nonmetals are either gas or solid at room temperature (except solid at room temperature (except bromine which is a liquid) bromine which is a liquid) They are not malleable or ductileThey are not malleable or ductileThey are lack lusterThey are lack lusterThey are poor conductors of They are poor conductors of electricity or heat electricity or heat

NonmetalsNonmetalsNonmetals tend to gain electrons Nonmetals tend to gain electrons (more on this later)(more on this later)

And have a high electro negativity. And have a high electro negativity.

AllotropesAllotropesSometimes certain non metals can Sometimes certain non metals can be found in nature in different be found in nature in different natural forms.natural forms.

Oxygen is found naturally as either Oxygen is found naturally as either OO22 or O or O3 3 (ozone)(ozone)Carbon can be found naturally as Carbon can be found naturally as diamonds or graphitediamonds or graphite

These forms are called Allotropes.These forms are called Allotropes.

Allotropes are when one elements can Allotropes are when one elements can have more then 1 natural form in have more then 1 natural form in nature.nature.

Allotropes are totally different from Allotropes are totally different from each other physically and chemically.each other physically and chemically.

MetalloidsMetalloidsMetalloids are elements that have Metalloids are elements that have some aspects of metals and some some aspects of metals and some aspects of non metals.aspects of non metals.

These elements are found touching These elements are found touching the Zigzag line. the Zigzag line.

TrendsTrendsLook up the EN and Ionization energy Look up the EN and Ionization energy in of all elements in period 3.in of all elements in period 3.

Do you see a pattern emerge as you Do you see a pattern emerge as you move across the table?move across the table?

Trends in ENTrends in ENAs we go across the table the As we go across the table the elements hold their electrons tighter elements hold their electrons tighter (Higher EN and Ionization E).(Higher EN and Ionization E).

This is because they have more This is because they have more protons to attract the electrons.protons to attract the electrons.

EN in a groupEN in a groupNow look up all the EN and Ionization Now look up all the EN and Ionization energies down group 2…energies down group 2…

Do you see a pattern?Do you see a pattern?

EN in groupsEN in groupsAs we go down a group the attraction As we go down a group the attraction for electrons get weaker. (lower EN & for electrons get weaker. (lower EN & ionization energy).ionization energy).

This is because the electrons move This is because the electrons move farther and farther away from the farther and farther away from the nucleus, so they are not as attracted.nucleus, so they are not as attracted.

going across EN & Ionization E go up going across EN & Ionization E go up going down EN & Ionization E go downgoing down EN & Ionization E go down

Since as we go across the table we Since as we go across the table we go from metals to non metal….go from metals to non metal….

As we go across the metallic As we go across the metallic properties increase. properties increase.

Atomic RadiusAtomic RadiusEach different element has atoms Each different element has atoms that are a different size.that are a different size.

Look up the atomic radius for group 2 Look up the atomic radius for group 2 and period 2. What is the trend?and period 2. What is the trend?

Properties of groupsProperties of groupsGroup one is called the Alkali metalsGroup one is called the Alkali metals

Group two is called the Alkaline earth Group two is called the Alkaline earth metalsmetals

These metals lose electrons easily & These metals lose electrons easily & become more reactive as we move become more reactive as we move down the groupdown the group

Group 17Group 17Group 17 is known as the halogens.Group 17 is known as the halogens.

It is the only group to have elements It is the only group to have elements that exist in all phases at room tempthat exist in all phases at room temp

Fluorine & chloride are gassesFluorine & chloride are gassesBromine is a liquidBromine is a liquidIodine is a solid. Iodine is a solid.

Group 18Group 18Group 18 is called the noble gasses.Group 18 is called the noble gasses.

They are always found as a gas and They are always found as a gas and ALMOST NEVER react. This is ALMOST NEVER react. This is because it has a full set of valence because it has a full set of valence electrons (more on this later)electrons (more on this later)

They are also called the inert gasses.They are also called the inert gasses.

Reactions between groupsReactions between groupsLook at the oxidation numbers in Look at the oxidation numbers in elements in group 1 and 17.elements in group 1 and 17.

What do you see.What do you see.

1 & 171 & 17Since group 1 elements gain a +1 Since group 1 elements gain a +1 charge and group 17 have a -1 charge and group 17 have a -1 charge they usually react in a 1:1 charge they usually react in a 1:1 ratio.ratio. ex, NaClex, NaClLiFLiFKClKClNaBrNaBr

2 & 162 & 16Look at the oxidation numbers of Look at the oxidation numbers of group 2 and 16 what do you see?group 2 and 16 what do you see?

2 & 162 & 16Since group 2 usually has a +2 Since group 2 usually has a +2 charge and group 16 has a minus 1 charge and group 16 has a minus 1 charge they usually react in a 1:1 charge they usually react in a 1:1 ratioratio

Ex: MgOEx: MgOBeSBeSCaOCaO

2 & 172 & 17Look at group 2 and 17 what ratio Look at group 2 and 17 what ratio will they react in?will they react in?

2 & 172 & 17Since group 2 has a +2 and group 17 Since group 2 has a +2 and group 17 has a -1 they usually have a 1:2 ratiohas a -1 they usually have a 1:2 ratio

Ex. BeClEx. BeCl22

MgBrMgBr22

CaFCaF22