The Periodic Table

PERIODIC appearing or occurring at intervals. Why is it labeled the Periodic Table? Name some things that are periodic: It is periodic because there are patterns that repeat each row or period.

A BRIEF HISTORY We have not always had the periodic table. The modern table as we know it is only about 100 years old.

A BRIEF HISTORY Father of the Periodic Table DMITRI MENDELEEV published 1869. He discovered a basic chemistry principle. He felt there was a certain pattern with the elements. - He tested his hypothesis that there was a periodic relationship among the elements. - He set up the periodic table by ATOMIC MASS and left blanks for undiscovered elements (three were later discovered).

MENDELEEV’S TABLE

A BRIEF HISTORY Father of the Modern Periodic Table HENRY MOSELEY 1913 - He saw some elements were out of place in Mendeleev’s table. He determined atomic numbers using x-rays. The elements were placed according to ATOMIC NUMBER. This was an important change. - This is the modern periodic table.

A BRIEF HISTORY The Final Changes to the Table Glenn Seaborg The last major change to the periodic table resulted from Glenn Seaborg's work. Starting with plutonium in 1940, Seaborg discovered transuranium elements 94 to 102 and reconfigured the periodic table by placing the lanthanide/actinide series at the bottom of the table. In 1951 Seaborg was awarded the Nobel Prize in chemistry and element 106 was later named seaborgium (Sg) in his honor.

Seaborg’s Contribution

WATCH The Genius of Dmitri Mendeleev

PERIODIC TABLE ORGANIZATION Columns - vertical, called groups (numbers) or families (names) - 18 total (8 main ones) - elements in the same column are not identical, but similar in properties.

PERIODIC TABLE ORGANIZATION ROWS horizontal, called periods, 7 total (at this time) elements are not alike in any way PATTERN: left side elements are active solids, far right side elements are inert (nonreactive) gases. Last two rows are rare earth elements. Atomic number increases from left to right.

1 2 3 4 5 6 7 6 7

ALTERNATIVE PERIODIC TABLES: SPIRAL

ALTERNATIVE PERIODIC TABLES: STOWE

ALTERNATIVE PERIODIC TABLES: TARANTOLA

ALTERNATIVE PERIODIC TABLES: MURADJAN

ALTERNATIVE PERIODIC TABLES: CHEMICAL GALAXY

ALTERNATIVE PERIODIC TABLES: 3D

CHARACTERISTICS OF THE PERIODIC TABLE Gases: hydrogen, helium, nitrogen, oxygen, fluorine, chlorine, neon, argon, krypton, xenon, radon. Liquids: mercury, bromine Solids: all the rest

PERIODIC TABLE Number the groups 1-18. Number the periods 1-7. Find element 92 (fourth one from the left in the bottom most row). Outline or lightly shade the elements that appear AFTER it in the row. Find the seventh period in the main table. Outline or lightly shade the elements that appear AFTER the first two in the row.

PERIODIC TABLE You have just outlined the synthetic elements, artificial elements, called the transuranium elements (“After” uranium). These are made in particle accelerators.

VALENCE ELECTRONS  The valence electrons are the electrons in the outermost shell or energy level of an atom. The valence electrons are the ones involved in forming bonds to adjacent atoms. Therefore, the number of valence electrons is important for determining the number of bonds an atom will form.

VALENCE ELECTRONS Group 1 1 valence electrons 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

VALENCE ELECTRONS

VALENCE AND ELECTRON DOT DIAGRAMS Valence electrons = electrons in outermost energy level of a Bohr Diagram. Electrons in outermost energy level of a Bohr Diagram = electrons in electron dot diagram SO Valence electrons = electrons in electron dot diagram

VALENCE AND ELECTRON DOT DIAGRAMS Element Period Group Valence Electrons Electron Dot Diagram Lithium   Fluorine Aluminum

We will look at how to draw electron dot diagram Wednesday. Skip the last column if you need to for now.

ANOTHER WAY TO LOOK AT THE TABLE All elements can be divided into three groups: METALS NONMETALS METALLOIDS

METALS

METALS located on the left side and center. good conductors of heat and electricity. hard and shiny (not always silver) can be pounded into different shapes - malleable can be drawn into a wire - ductile high density, high melting points react with water and substances in the atmosphere (ex. rusting, tarnishing)

METALS has only a few electrons in the outer level most elements are metals. General rule: 3 or fewer electrons in outer level are considered to be metals. Metals have a tendency to lose electrons when forming compounds.

NONMETALS

NONMETALS located on the right side (except hydrogen) poor conductors of heat and electricity (solids are insulators) brittle solids or gases or liquids dull shatter easily lower density, lower melting points

NONMETALS not as easy to recognize as a group has more than 4 electrons in the outer level. General rule: 5 or more electrons in outer level are considered to be nonmetals. Nonmetals have a tendency to gain electrons when forming compounds

METALLOIDS

METALLOIDS Sometimes called semi-metals. have properties of metals and nonmetals “metal-like” located on either side of the staircase all are shiny, white-gray in color all are solids okay conductors (as in semi-conductors), ductile, malleable

METALLOIDS There are seven: Boron, Silicon, Germanium, Arsenic, Antimony, Tellurium, Astatine Aluminum is NOT a metalloid. Polonium is sometimes classified as a metalloid.

METALLOIDS

UNKNOWN METALS LAB Introduction: Most of the elements on the periodic table are metals and solids. These elements have observable properties that make it possible to identify an unknown element. Density is one of the properties that can be used to identify an unknown metal. As you know, density is the ratio of mass to volume. In equation form: Density = Mass ÷ Volume.

THE ELEMENT FAMILIES

HYDROGEN – a special case one valence electron Considered a nonmetal; Not part of Group One; acts as a metal and a nonmetal; most abundant element in the universe; flammable

ALKALI METALS – group 1

GROUP 1: ALKALI METALS Early in human history, people discovered that ashes mixed with water produced a slippery solution useful for removing grease. By the Middle Ages, such mixtures were described as alkaline, a term derived from the Arab word for ashes, al-qali. Alkaline mixtures found many uses, particularly in the preparation of soaps. This is why they are called alkali metals. We now know that alkaline ashes contain compounds of Group 1 elements, most notably potassium carbonate (potash).

ALKALI METALS – group one one valence electron; very reactive Most reactive is francium; not found in nature by themselves; low electron affinity SODIUM and POTASSIUM important to body functions FRANCIUM – most reactive metal, but extremely rare

GROUP TWO: ALKALINE EARTH METALS

ALKALINE EARTH METALS – group two Elements in group 2 also form alkali solutions when placed in water. Medieval alchemists noted that certain minerals do not melt or change when put into fire – we know these as group 2 elements. These fire-resistant substances were known to alchemists as earth. As a holdover from these ancient times, group 2 elements are known as alkaline earth metals.

ALKALINE EARTH METALS – group two two valence electrons; less reactive, but similar to alkali metals; low electron affinity, CALCIUM – 5th most abundant element on earth (lime, calcium chloride, body functions)

GROUPS 3-12: TRANSITION ELEMENTS

TRANSITION ELEMENTS – groups 3-12 The elements in groups 3-12 are all metals that do not form alkaline solutions with water. These metals tend to be harder than alkali metals and less reactive with water. They are used for structural purposes. Their name – transition metals – denotes their central position in the periodic table.

TRANSITION ELEMENTS – groups 3-12 Two, three, or four valence e-; They all have properties similar to one another and to other metals: resistant to corrosion, high melting points, brittle These metals are less reactive than Group 1 or 2, and are harder. Include IRON (steel), CADMIUM (batteries), COPPER (wiring), COBALT (magnets), SILVER (dental fillings), ZINC (paints), GOLD (jewelry)

GROUP 13: Boron Family

Boron Family – group 13 three valence electrons includes metalloids and metals BORON – metalloid; ALUMINUM – most plentiful metal in the earth's crust, has the most practical uses GALLIUM – low melting point, component of blue lasers.

GROUP 14: CARBON FAMILY

CARBON FAMILY – group 14 four valence electrons; generally react by sharing electrons, Consists of a nonmetal, metalloids, and metals; CARBON – most versatile element can form millions of compounds; field of organic chemistry; has several allotropes: graphite, diamond, fullerene, carbon black SILICON – second most plentiful element in the earth’s crust (quartz); many industrial uses. LEAD – toxic; used to be in paint, plumbing, gasoline

GROUP 15: NITROGEN FAMILY also called Pnictogen Family

NITROGEN FAMILY – group 15 five valence electrons; Consists of nonmetals, metalloids, and a metal Sometimes will share its five electrons NITROGEN – found in fertilizers, TNT, medicines, proteins PHOSPHORUS – compounds found in laxatives, cheese, and baking powders

GROUP 16: OXYGEN FAMILY also called Chalcogens

OXYGEN FAMILY – group 16 six valence electrons; Consists of nonmetals and metalloids OXYGEN - very reactive; most plentiful element in the earth’s crust; forms compounds with practically every element (except neon, argon, and helium); has two allotropes, O2 and O3.

ALLOTROPES Different forms of the same element. Examples: Oxygen,O2 and ozone, O3 Carbon – diamond, graphite, charcoal

DIATOMIC MOECULES a molecule that consists of two atoms of the same element. There are seven diatomic molecules: H2, N2, O2, F2, Cl2, Br2, and I2 Noble gases are NOT diatomic.

DIATOMIC MOLECULES

GROUP 17: HALOGEN FAMILY

HALOGEN FAMILY – group 17 Called Halogens - Swedish for “salt-forming”; seven valence electrons high electron affinity, FLUORINE - most reactive nonmetal (element) due to its size; most electronegative element; reacts with all elements but neon, helium, and argon. CHLORINE – deadly gas; compounds act as bleaching agents and disinfectants IODINE – used to disinfect water and wounds (tincture of iodine)

GROUP 18: NOBLE GAS FAMILY

NOBLE GAS FAMILY – group 18 Nonreactive gases that tend not to combine with other elements. They are called the Noble gases, presumably because the nobility of early times were above interacting with the common people.

NOBLE GAS FAMILY – group 18 eight valence electrons (except Helium which has two) has stable outer electron configurations and all electron energy levels are full; low electron affinity HELIUM – used in scuba diving; balloons NEON, ARGON – lighting

INNER TRANSITION ELEMENTS – no group number

INNER TRANSITION ELEMENTS – no group number

INNER TRANSITION ELEMENTS – no group number In the sixth and seventh periods, there are a subset of 28 metallic elements that are quite unlike any of the other transition elements. Inserting the inner transition elements into the main body of the periodic table results in a long and cumbersome table, so these elements are pulled out below the table so it can fit nicely on a 8.5” x 11” piece of paper. These two rows have no group number.

INNER TRANSITION ELEMENTS – no group number The elements in each subset have properties that are so similar to one another that each subset can be viewed as a group. Include the Lanthanides and the Actinides, names after the first element in each group.

INNER TRANSITION ELEMENTS – no group number LANTHANIDES: silvery metals with high melting points high luster and conductivity Tend to be mixed together in the same geologic zones and are hard to separate since they are so similar; used in making high quality glass, television screens, lasers, tinted sunglasses, LEDs

INNER TRANSITION ELEMENTS – no group number ACTINIDES: Have similar properties and are not easily purified. This is a problem for the nuclear industry as it requires purified samples of uranium and plutonium. all are radioactive 93-103 are synthetic (transuranium elements) Most common are URANIUM and PLUTONIUM - used as nuclear fuel.

OR Why we call it the PERIODIC table PERIODIC TRENDS OR Why we call it the PERIODIC table

PERIODIC REMEMBER: It is periodic because there are patterns that repeat each row or period.

PERIODIC TRENDS Elements have properties because of their atomic number which tells the number of electrons and thus the valence electrons. Same column = similar valence electrons Properties that are periodic: metals/metalloids/nonmetals, boiling point, density, atomic radii, ionic radii, oxidation numbers, ionization energies, electron affinities, electronegativity

Boiling Point of the Elements

IONIZATION ENERGY

ALKALI METALS Which element had the largest reaction? Any idea why?

ATOMIC RADII (size) As the electron energy levels increase down a group, the period number increases , and so does the atomic radii. As the atomic number increases across a period, the positive charge also increases within the same energy level and so the electrons are more attracted to the nucleus TREND: atomic radii increases down a group, atomic radii decreases across a period.

ATOMIC RADII

ELECTRON AFFINITY The attraction of an atom for an electron. If an element has a high electron affinity, it really wants to gain an electron. TREND: Metals have LOW electron affinities Nonmetals have HIGH electron affinities (except the Noble Gases).

SUMMARY Noble Gases: - Eight valence electrons (except helium) - atomic radii large for their row - Electron Affinity LOW

SUMMARY Halogens: - Seven valence electrons - atomic radii lowest for their row - Electron Affinity HIGH

SUMMARY Alkali Metals - one valence electron - Atomic radii largest for their row - Electron Affinity LOW

SUMMARY Alkaline Earth metals: - two valence electrons - Atomic radii second largest for their row - Electron Affinity LOW Thanks to Mrs. Brim at East Jackson for the periodic Table Notes!