PowerPoint Presentation

Properties of the Periodic TableThe Periodic TableVertical columns are called GroupsGroups are numbered from 1 to 18

Valence Electrons are electrons located on the outermost energy level.

Each element in a group has the same number of valence electrons

The Periodic TableEach row is called a periodEach period starts with an atom with one electron in the outer energy level and ends with an atom that has a full outer energy level

The Periodic TableThe Periodic Table has 3 main sections of elements with similar properties:

MetalsNonmetalsMetalloids

The Periodic TableSpecifics on Groups of the Periodic TableMetalsProperties of metals include:

Conduct heat & electricity

Solid at room temperature - all except Mercury (Hg)

MetalsProperties of metals include:

Reflective, malleable, ductile

Located on the left side of the Periodic Table

Alkali MetalsAlkali MetalsThe first column of the periodic table

Forms +1 Ions by losing the 1 valence electron

The most reactive metals on the periodic table

Sodium explodes when exposed to the air

http://video.google.com/videoplay?docid=-2134266654801392897#

Alkaline Earth MetalsAlkaline Earth MetalsSecond group on the periodic table

Also very reactive, but not as much as the alkali metals

Forms +2 Ions by losing the 2 valence electrons.

Transition ElementsGroups 3-12 are the more stable Transition Elements

They usually exist uncombined with other elements because they are not as reactive

Transition ElementsUsually form multiple positive ions. i.e. Copper forms +1 or +2 depending on the compound.

Inner Transition ElementsThe disconnected rows underneath the rest of the table

They fit between groups 3 & 4 in periods 6 & 7

The first row contains the Lanthanides, starting with LanthanumThe second row contains the Actinides, starting with ActiniumThey are very unstable because of the high number of neutrons versus protons

Inner Transition Elements

NonmetalsNonmetalsProperties of nonmetals:

Usually gases or brittle solids at room temperature

Exception is Bromine (liquid)NonmetalsProperties of nonmetals:

Not malleable or ductile

Not usually conductive or reflective

Form negative ions by gaining valence electrons.

Noble GasesNoble GasesThey are in group 18 of the periodic table

They are the most stable of all elements. They dont react with other elements under normal conditions

HalogensHalogensGroup 17 on the periodic table

They are not usually found in nature alone but as salts (Combined with a metal)

Some are called diatomic molecules (exist in a molecule of 2 atoms)

HalogensReadily gain 1 valence electron to form a -1 ion.

Halogens are very reactive

The most reactive non-metals!

Diatomic Molecules Some nonmetals are called diatomic because they exist as a molecule of two atoms joined together

This means that Natural Oxygen exists as O2

MetalloidsMetalloidsElements that have properties of metals and nonmetals

Groups 13, 14, 15, 16, and 17 contain metalloids

MetalloidsThe metalloids are: BoronSiliconGermaniumArsenicAntimonyTelluriumPoloniumMetalloidsHave a combination of the properties of metals and non-metals

In a zig-zag from top of Boron to the bottom of Polonium

Periodic TrendsPeriodic TrendsThe periodic table is organized in such a way that repeating patterns, or trends, can be seen.

There are three main trendsAtomic massAtomic radiusReactivity

Periodic TrendsAtomic Mass TrendAs you go from left to right, mass increases

As you go from top to bottom, mass increases

Atomic Mass TrendWhy?As we go left to right or top to bottom, there is an increase in amount of matterProtons and Neutrons increase

Which has more mass?For ON or AsNaor KSror LiHor Xe

Atomic Radius (Size) TrendAtomic Radius is the distance from the center of the nucleus to the outside of the electron cloudMeasure in Angstroms ()

As you go from left to right, radius decreasesAs you go from top to bottom, radius increases

Atomic Radius (Size) TrendWhy? As we go left to right , the nucleus pulls the atom tighter.

Top to bottom, there are more energy levels being added.

Atomic Radius (Size) TrendWhich has a bigger radius?For ON or AsNaor KSror LiHor Xe

Reactivity Trend Tells how reactive elements are, or how strongly they will interact with other elements

As you go from left to right, reactivity of metals decreases, and then the reactivity of nonmetals increases (but stops at the halogens)

Reactivity Trend As you go from top to bottom, reactivity increases on the left and decreases on the right

Why?Metals at the bottom lose electrons and nonmetals at the top gain electrons.

Therefore the corners are the most reactive.

Reactivity Trend Most Reactive Metal and Nonmetal Start with F

Can you guess what they are?

Remember the Alkali metal reactivity videohttp://video.google.com/videoplay?docid=-2134266654801392897#

Bohr ModelsOne way to see the trend of Valence Electrons is to draw a Bohr model.

Remember Bohr placed electrons in specific orbits, or energy levels.

1st = 2 electrons 2nd = 8 electrons 3rd = 18 electrons 4th = 32 electrons

Bohr ModelsLets Draw the Bohr models for some of the elements in group 1

What do you notice?

Lewis Dot DiagramsSoon we will learn that although as many as 32 electrons can sit on an outer energy level, we are only concerned about the outermost 8, which are the valence electrons.

This is what we call an Octet. (8 Electrons)

Lewis Dot DiagramsWe show how an elements octet is filled using a Lewis Dot structure.

Lets draw the Lewis Dot Diagrams for the same atoms and some new ones.

Valence ElectronsValence Electrons become VERY important in our next unit!!!

Lewis Dot Diagrams