Periodic Table

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www.middleschoolscience.com 2008

3/5/14 IQ

• Discuss what happens when an energy level gets full with the amount of electrons it can hold

Energy Levels

• Electrons are arranged in energy levels.• Electrons with the lowest energy can be found in the

energy level closest to the nucleus.• Energy levels can hold 2, 8, 18• The first 18 elements can hold:• 1st level: 2 electrons• 2nd level: 8 electrons• 3rd level: 8 electrons

*When you get into higher numbered elements, we go to the 2,8,18 shells

Valence Electrons

• Electrons in an atom are not all the same distance from the nucleus. Electrons farthest away from nucleus are called valence electrons.

• Valence electrons are involved in chemical bonds.

• Group 1: 1 valence electron• Group 2: 2 valence electrons• Group 13: 3 valence electrons• Group 14: 4 valence electrons• Group 15: 5 valence electrons• Group 16: 6 valence electrons• Group 17: 7 valence electrons• Group 18: 8 valence electrons -- except for

helium, which has 2

• The # of Valence electrons an atom has is dictated by the Group (vertical column) the element is in.

Examples:Mg= Group _2__ A so it has ____ valence

electrons. Li= Group _1__ A so it has ____ valence

electrons.

Valence Electrons the Quick and Easy Way

133A5B

Boron

13Al

Aluminum31Ga

Gallium

Use the group

number!All of the elements in Group 13 or will have three valence electrons.

Valence Electrons the Quick and Easy WayDetermine the number of valence electrons.

•Phosphorus•Argon•Lead•Barium

5 valence electrons

8 valence electrons

4 valence electrons

2 valence electrons

Electron Dot Diagram• Used to represent the valence electrons of an atom.• Elements can have between 1-8 valence electrons.• During a chemical bond the element usually ends up with

either 0 or 8 valence electrons.

Determine the number of shells and the number of valence electrons for:

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Determine the number of shells and the number of valence electrons for:

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• Helium is the exception in Group 8.

• Since it has just one shell, that shell can only fit 2 electrons instead of 8.

• It is in this group because all the elements have a full outer shell.

Chemical Bonds• Forms between two atoms when valence electrons move

between them. The valence electrons may be transferred from one atom to another, or they may be shared.

• If the valence shell is full, then the element is inert. If the valence shell isn't full, then the element is reactive, which means that it can form a bond with an atom of another element. Each atom shares its valence electrons in an attempt to complete its own valence shell.

• Atoms tend to be most stable with a full outer shell

• Atoms that do not have full outer shells will tend to gain or lose electrons, resulting in a full outer shell, creating stability

Drawing a Carbon Atom

IQ 3/3/14• Describe one way that the periodic table is arranged.

Modern Periodic Table

• Period: Horizontal row. Properties of elements follow a repeating, or periodic pattern as you move across each row.

• Family/Group: Vertical column. Elements in the same group often have similar chemical and physical properties

• Elements are arranged by increasing atomic number (#of protons)

• An element’s properties can be predicted from its location on the table.

• Across the row or down a column the elements’ properties change in a predictable way.

We Do Together: Please get out a separate sheet of paper Draw a model of each atom. Lithium Boron Oxygen Potassium

Include: Correct number of protons and neutrons in the nucleus Correct number of electrons, in their corresponding energy levels IS YOUR LAST ENERGY LEVEL FULL? YES OR NO? Use page 744 as a guide.

YOU DO: Classwork: On a separate sheet of paper, Draw a model of each atom. Helium Neon Aluminum Chlorine

Include: Correct number of protons and neutrons in the nucleus Correct number of electrons, in their corresponding

energy levels IS YOUR LAST ENERGY LEVEL FULL? YES OR NO? Use page 744 as a guide.

IQ 3/10/14

• What does a group tell you on the periodic table?

• What does a period tell you?

Groups or Families

• Elements in a column.• Numbered 1 on left to 18 on right.• Elements in a group have similar

characteristics.• They have the same number of valence

electrons (electrons in the outermost shell/level).

Groups cont.

• Based on their chemical properties.• Each group has a specific name to

differentiate it from other groups in the periodic table.

• Elements in each group react differently with other elements.

Periods or Rows

• Contains a series of elements from different groups.

• The elements have very different properties.• 7 periods of elements.• 7 electron shells• The elements change in a predictable way from

left to right. • Most reactive to least reactive

Periods•The elements in each period have the same number of shells

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Groups

•Each column is called a “group”

•Each element in a group has the same number of electrons in their outer orbital, also known as “shells”.

Except for He, it has 2 electrons

•The electrons in the outer shell are called “valence electrons”

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IQ 3/11/14

• Describe some characteristics about metals.

• What are some common uses of metals?

Metals• Found on the left of the

zig-zag line.• Metals are based on

physical properties of hardness, shininess, malleability, ductility.

• Malleability means that it can be pounded into shapes.

• Ductility means that the metal can be pulled out or drawn into a long wire.

• Conductors – most metals can transmit heat and electricity easily.

• Magnetic – several metals can be made into magnets or are attracted to magnets. (iron, cobalt, nickel)

Chemical Properties of Metals

• Some very reactive – sometimes explosive others not reactive at all.

• Metals on the left of the table, Family 1, are the most reactive and they become less and less reactive as you move right.

ALKALI METALS

Group 1• Hydrogen is not a member, it is a non-

metal• 1 electron in the outer shell, which can

be easily given away• Soft and shiny, silvery metals• Very reactive, esp. with water• Conduct electricity• Never found alone in nature, always in

a compound.

Image: http://www.learner.org/interactives/periodic/groups2.html

ALKALINE EARTH METALSGroup 2• 2 valence electrons, which

they can easily lose• White and malleable• Reactive, but less than Alkali

metals• Conduct electricity• Not as reactive as Group 1 but

more reactive than most metals.

TRANSITION METALSGroups in the middle

Good conductors of heat and electricity.

Some are used for jewelry. The transition metals are able to put

up to 32 electrons in their second to last shell.

Can bond with many elements in a variety of shapes.

• Group 3 – 12• Form a bridge between the very

reactive metals on the left side and the less reactive metals on the right.

• Very similar so that it is difficult to detect differences from one column to the next.

• Fairly stable, reacting slowly or not at all with air and water.

Metals in Mixed Groups• Groups 13 – 16 include: metals, nonmetals, metalloids.

• The metals to the right of the transition metals are not as reactive as Groups 1 &2.

Bonding in MetalsMost have 1-3 valance electrons which they lose easily.Usually lose the electron to a nonmetal and form ionic bonds.

Sometimes metallic bonding occurs – the positively charged ions are surrounded by a sea of electrons. The electrons can slide past each other . This is how they are malleable, ductile, and good conductors of electricity. Page 331.

For example, during the reaction of sodium with chlorine:

                            sodium

(on the left) loses its one valence electron to chlorine (on the right),

   resulting in

                            a

positively charged sodium ion (left) and a negatively charged chlorine ion (right).

The reaction of sodium with chlorineConcept simulation - Reenacts the reaction of sodium with chlorine.

(Flash required)

Metal Facts

• Aluminum most abundant metal in the Earth’s crust.

• Iron second most abundant. Metals must be dug or mined from earth’s crust.

• Iron is most widely used metal (steel), cobalt is sometimes used in steel.

• Nickel gives it the shiny color.

Nonmetals and Metalloids

Where are they located on the periodic table?

•What are the properties of nonmetals and metalloids?

What is a Nonmetal?

• 17 Nonmetals located to the right of the zig-zag line on the PT.

• Physical properties are the opposite of metals.

Physical Properties

• Dull (non shiny), brittle (breaks easily), low densities, poor conductors of heat and electricity.

• Many non metals are gases at room temperature

Chemical Properties

• Most nonmetals form compounds. They gain/take or share electrons.

• Family/Group 18 do not. This is because they have 8 valence electrons in their outermost energy level.

• When nonmetals and metals react the valence electron moves from the metal to the nonmetal.

• Find for each atom:• Atomic number Atomic mass• Group Period

Metalloids

• Borders between metals and nonmetals and have characteristics of both metals and nonmetals

• Semiconductor (able to conduct electricity at room temperature more easily than an insulator, but less easily than a metal)

• Reactivity depends on properties of other elements in reaction

BORON FAMILY

Group 3• 3 electrons in the outer

shell• Most are metals• Boron is a metalloid

CARBON FAMILY Group 4• 4 electrons in the outer shell• Contains metals, metalloids,

and a non-metal Carbon (C)• 4 valence electrons• Carbon is the only nonmetal.• All living things contain

compounds that are made of carbon atoms.

NITROGEN FAMILY Group 5• 5 electrons in the outer

shell• Can share electrons to

form compounds• Contains metals,

metalloids, and non-metals• Group 15 – 5 valence

electrons• Atmosphere is 80 %

nitrogen

OXYGEN FAMILY Group 6• 6 electrons in the outer shell• Contains metals, metalloids, and

non-metals• ReactiveGroup 16, 6 valence

electrons.• Usually gain or share 2 valence

electrons.• Oxygen is a diatomic molecule • Oxygen is very reactive – it can

combine with nearly all elements.

• Most abundant element in the Earth’s crust, 2nd most abundant in the atmosphere.

HalogensGroup 7• 7 electrons in the outer shell• All are non-metals• Very reactive are often

bonded with elements from Group 1Group 17

• contains fluorine, chlorine, bromine, iodine, astatine.

• 7 valence electrons, gains or shares one valence electrons when it reacts.

Noble GasesGroup 8 Exist as gases Non-metals 8 electrons in the outer shell = Full Helium (He) has only 2 electrons in

the outer shell = Full• Not reactive with other

elementsGroup 18, do not mix with others.

• Do not gain, share, lose electrons.• Chemically stable because they

have a full outer energy level.• Group 18 is the only family that

consists of all nonmetals.

Rare Earth Metals• Some are

Radioactive• The rare earths

are silver, silvery-white, or gray metals.

• Conduct electricity

Iron, Cobalt, Nickel• First elements in groups 8,9, 10 called the iron triad.• The only ones known to create a magnetic field.

Hydrogen• Alone in the upper left corner.• Simplest element – usually its atoms contain one proton and

one electron.• Hydrogen is rarely found on Earth as an element. Usually

combined with oxygen as water.