The Periodic Table of The

Elements

Periodic Table of Elements

• The structure and properties of atoms are used to organize the periodic table, just as a grocery store organizes food by its properties.

The Periodic Table

• Arrangement of the known elements based on atomic number and chemical and physical properties.

• Divided into three basic categories:•Metals• Nonmetals•Metalloids

Basic Organization

The periodic table is organized by:

• Atomic Structure• Atomic number• Chemical and Physical Properties

Uses of The Periodic Table

The periodic table is useful in predicting:

• chemical behavior of the elements• trends• properties of the elements

Atomic Structure Review• Atoms are made of protons, electrons, and

neutrons.

• Elements are atoms of only one type.

• Elements are identified by the atomic number (# of protons in nucleus).

Energy Levels Review

• Electrons are arranged in a region around the nucleus called an electron cloud. Energy levels are located within the cloud.

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

Energy Levels Review

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

• Inner levels will fill first before outer levels.

Energy Levels & Valence Electrons

• Energy levels hold a specific amount of electrons:

– 1st level = up to 2 – 2nd level = up to 8 – 3rd level = up to 8 (first 18 elements only)

Energy Levels & Valence Electrons

• The electrons in the outermost level are called valence electrons.

– Determine reactivity - how elements will react with others to form compounds

– Outermost level does not usually fill completely with electrons

Using the Table to Identify Valence Electrons

• Elements are grouped into vertical columns because they have similar properties.

• These are called groups or families.• Groups are numbered 1-18.

Using the Table to Identify Valence Electrons

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

valence electrons.

Using the Table to Identify Valence Electrons cont.

• Groups 13–18 have 10 fewer than the group number. For example:

– Group 13 has 3 valence electrons.– Group 15 has 5 valence electrons.– Group 18 has 8 valence electrons.

Elements & Reactivity

• Reactivity is a chemical property that determines how elements will react with others to form compounds.

Elements & Reactivity

• What makes an element reactive?●Number of valence electrons each atom has●When outer levels are full, atoms are stable.●When they are not full, they react:

●gain, lose, or share 1 or 2 electrons.

Elements & Reactivity• The most reactive metals are the elements in

Groups 1 and 2.

– Elements in Group 1 need seven more electrons to fill their outer level.

– Elements in Group 2 need six more electrons to fill their outer level.

• These groups are known as the “givers” because they easily give up their valence electrons to make a compound.

Elements & Reactivity• The most reactive nonmetals are the elements

in Groups 16 and 17.

– Elements in Group 16 only need two more electrons to fill their outer level.

– Elements in Group 17 only need one more electron to fill their outer level.

• These groups are known as the “takers” because they easily receive valence electrons to make a compound.

Groups • Groups run vertically in the periodic table. • They are numbered from 1–18.• Elements in the same groups have the same

number of valence electrons in the outer energy level.

• Grouped elements behave chemically in similar ways.

Periods• Periods run horizontally across the Periodic

Table• Periods are numbered 1–7• All the elements in a period will have the same

number of energy levels, which contain electrons. Examples:– Period 1 atoms have 1 energy level.– Period 2 atoms have 2 energy levels.– Period 5 atoms have 5 energy levels.

Periods Continued• Moving from left to right across a period, each

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

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

Group 1: Alkali Metals• Contains: Metals• Valence Electrons: 1• Reactivity: Very Reactive• Properties: – solids– soft– react violently with water– shiny – low density

Group 2: Alkaline-Earth Metals

• Contains: Metals• Valence Electrons: 2• Reactivity: very reactive, but less reactive than

alkali metals (Group 1)• Properties: – Solids– Silver colored– More dense than alkali metals

Groups 3-12 Transition Metals

• Contain: Metals• Valence electrons: 1 or 2• Reactivity: less reactive than alkali and

alkaline-earth metals• Properties:– Higher density– Good conductors of heat and electricity

Groups 3-12 Transition MetalsBelow Main Table

• Contain: The Lanthanide and Actinide Series– These two rows are pulled out of sequence and

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

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

Groups 3-12 Rare Earth Elements ~ Lanthanides

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

• Valence electrons: 3• Reactivity: Very reactive• Properties:

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

Groups 3-12 Rare Earth Elements ~ Actinides

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

• Valence electrons: 3 (but up to 6)• Reactivity: unstable– All are radioactive– Most made in laboratories

Metalloids • A zig-zag line that separates metals from

metalloids• Elements from Groups 13–17 contain some

metalloids.

• These elements have characteristics of metals and nonmetals.

Group 13: Boron Group

• Group 13: Boron Group• Contains: 1 metalloid and 4 metals• Valence Electrons: 3• Reactivity: Reactive• Other shared properties:– Solid at room temperature

Group 14: Carbon Group

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

• Valence Electrons: 4• Reactivity: Varies• Other shared properties: – Solid at room temperature

Group 15: Nitrogen Group

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

• Valence electrons: 5• Reactivity: Varies• Other shared properties: – All but N are solid at room temperature

Group 16: Oxygen Group

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

• Valence Electrons: 6• Reactivity: Reactive• Other shared properties: – All but O are solid at room temperature.

Groups 17 : Halogens

• Contain: Nonmetals• Valence Electrons: 7• Reactivity: Very reactive• Other shared properties

●Poor conductors of electric current●React violently with alkali metals to form salts●Never found uncombined in nature

Group 18 Noble Gases

• Contains: Nonmetals• Valence Electrons: 8 (2 for He)• Reactivity: Unreactive (least reactive group)• Other shared properties: – Colorless, odorless gases at room temperature– Outermost energy level full– All found in atmosphere

Hydrogen Stands Apart

• H is set apart because its properties do not match any single group.

• Valence electrons: 1• Reactivity: very, but loses the 1 electron easily• Properties:– Similar to those of non-metals rather than metals

Properties of Metals,Metalloids and Nonmetals

• Sheet of notebook paper.• Fold into thirds.• Label each column appropriately.

Henning Brand - 1649Around 1669 he heated residues from boiled-down urine on

his furnace until the retort was red hot, where all of a sudden glowing fumes filled it and liquid dripped out, bursting into flames. He could catch the liquid in a jar and cover it, where it solidified and continued to give off a pale-green glow. What he collected was phosphorus, which he named from the Greek word for "light-bearing" or "light-bearer."

A. E. Beguyer de Chancoutois - 1817

French geologist and mineralogist who was the first to arrange the chemical elements in order of atomic weights.

Johann Dobereiner - 1862

These sets of elements became known as "Dobereiner's Triads".

Döbereiner discovered trends in certain properties of selected groups of elements

John Newlands - 1863

Law of Octaves

Lothar Meyer - 1864known for the share he had in the periodic classification of the elements

noted that if they are arranged in the order of their atomic weights they fall into groups in which similar chemical and physical properties are repeated at periodic intervals

Valence IV Valence III Valence II Valence I Valence I Valence II The mass difference

I line Li Be ~16

II line C N O F Na Mg ~16

III line Si P S Cl K Ca ~45

IV line As Se Br Rb Sr ~45

V line Sn Sb Te I Cs Ba ~90

VI line Pb Bi Tl ~90

Dmitri Ivanovich Mendeleev - 1869formulated the Periodic Law, created his own version of the periodic table of elements, and used it to correct the properties of some already discovered elements and also to predict the properties of elements yet to be discovered.

Lord Rayleigh - 1895

• discovered argon

Ernest Rutherford - 1911

he theorized that atoms have their charge concentrated in a very small nucleus

Henry Moseley - 1913

• proposed that the atom contains in its nucleus a number of positive nuclear charges that is equal to its (atomic) number in the periodic table

Glenn Seaborg - 1940

contributed to the discovery and isolation of ten elements, and developed the actinide concept, which led to the current arrangement of the actinide series in the periodic table of the elements

True or False

1. The following elements all belong to the same period:

Ne, Ar, Kr, Xe

2. The following elements all belong to the same group/family:

H, Li, Na, K

• 3. All elements in groups 13 have 3 valence electrons.

• 4. The chemical reactivity of an element is determined by its protons.

• 5. Mg is chemically similar to Ca.

Article Review• As you are reading:– Underline at least 4 statements of something you did not

know before reading.

– Circle at least 2 words you do not know the meaning of.

– Highlight the main ideas in the article: Who, what, when, where and why

– Put a star * by something you read that you thought was interesting.