The Periodic Table

The Periodic Table

Dmitri Mendeleev - 1869 • Mendeleev was born in Siberia, Russia in the year 1834. He died in 1907 • He was a professor of Chemistry at the St. Petersburg University. Trying to explain to his students how elements had similar properties, he started organizing the elements into rows and columns • He observed that some elements have similar chemical & physical properties • The first periodic table was organized by atomic mass • The masses were compared to Hydrogen, the lightest known element at the time. • The modern Periodic Table is organized by Atomic number

Organizing the Elements • The periodic table is laid out by increasing atomic number as you go across and down the table Atomic # increases  Atomic # increases 

Periods, Groups & Families Groups & Families are in vertical columns, there are 18 Groups PeriodsareRows There are 7 numbered Periods and 18 numbered Groups Families are named in 2 ways, 1st after the top element in the column, The Oxygen Family contains O, S, Se, Te & Po. 2nd way to name them is w/ their “old fashion” names. (see next slide)

“Need-to-Know Families “Old Fashion Names” of certain Families Alkali Metals Alkaline Earth Metals Noble Gases Halogens Chalogens

More Need-to-Knows Transition Metals Actinides Lanthanides Rare Earth Elements – AKA Inner Transition Metals

Parts of an Atom • An atom consists of a nucleus surrounded by one or more electrons • Atoms are electrically neutral w/ the same number of protons as electrons. • Majority of the atom is empty space. If nucleus were the size of a pencil eraser, the closest electron would be 100 yards away! • Subatomic Particles • Protons • Neutrons • Electrons

Parts of an Atom • Subatomic Particles • Protons • Neutrons • Electrons • Nucleus: Tightly packed Protons & Neutrons • Electrons Orbiting nucleus @ 1 % speed of light!!

Atomic Number • By definition: The Atomic Number = the number of Protons present in the nucleus of an atom Each Element in the Periodic Table has a different number of Protons, therefore each element has a different, unique, atomic number.

Atomic Number When reading the Periodic table, notice each element has a unique 1 or 2 letter symbol and “big” & “small” number listed “Small” number is always the Atomic Number, therefore the number of protons present “Large” number is always the Atomic Mass which tells us the total # of both Protons & Neutrons present

Atomic Mass • How much does an atom “weigh”? • What is the mass of an atom? • SI Unit for mass is the Gram…. Way toooo big to accurately “mass” an atom • Came up w/ new unit, an AMU (atomic mass unit) • 1 AMU = mass of 1 Proton

Atomic Mass • mass of subatomic particles • Proton = 1 AMU • Neutron = 1 AMU • Electron = .0005 AMU • Atomic Mass = the total # of both Protons & Neutrons in the atom • ( we don’t worry about the mass of the electrons since they have almost no mass)

How many Neutrons are there? • Remember: • The Atomic # = the # of Protons • The Atomic mass = The # of both Protons & Neutrons. • Therefore, if you subtract the Atomic # (the number of Protons) from the Atomic mass (the number of both Protons & Neutrons) what is left over must be the number of Neutrons!!

How many Neutrons are there? For Example w/ Carbon: Atomic Mass-Atomic # = # Neutrons Atomic Mass = 12, Atomic # 6 12 – 6 = 6 Therefore there are 6 neutrons present in the Carbon nucleus If you don’t believe me… just count for yourself.

Electrical Atomic Charge • Electrical charge – all atoms have a neutral charge • ( a zero net electrical charge) • Protons have a positive (+) electrical charge • Neutrons have a neutral (0) electrical charge • Electrons have a negative (-) electrical charge • Since the net electrical charge is 0 (neutral), if you have 10 Protons (10 “+” charges) then there must be 10 “-” charges (10 electrons) present to balance out the atom. • Therefore, as long as you know the Atomic #, you know the # of Protons and also the # of Electrons!!

The Alkaline Earth Metals – Group 2 • not as reactive as Alkali Metals, but still very reactive. They have two valence electrons and generally give them up to nonmetals to form ionic bonds. Examples include Calcium and Magnesium

The Alkali Metals – Group 1 • Very reactive metals that have only one valence electron in the outer orbit and will freely give it away to become stable. Very soft metal (you could cut it w/ a plastic knife!). They form ionic bonds w/ Halogens and Chalogens. Examples include Sodium and Potassium.

Noble Gases - Group 18 • Non reactive, have a full compliment of valence electrons, 8 and are called the “Inert Gases” because they do not react w/ other elements. Examples include Helium (very low mass and is used in filling children’s balloons and even airships and the “Goodyear Blimp) and Neon used in lighted bulbs to make a red glowing light ( a neon light).

Halogens – Group 17 • Very reactive nonmetals w/ 7 valence electrons. Need only one more electron to fill their outer shell. Will steal an electron from a reactive metal to form ionic bonds. Examples include Fluorine ( the most reactive nonmetal), Chlorine (the most abundant halogen), Iodine and Bromine (found in Seawater).

ChalogensAKA: Oxygen Family – Group 16 • nonmetals w/ 6 valence electrons, need 2 electrons to fill the outer shell. Oxygen’s most common oxidation state is -2. Examples are Oxygen (ozone is one of its allotropes), Sulfur (responsible for that rotten egg smell when it combines w/ oxygen to form sulfur dioxide) and Selenium (one of the few non metals that are also a good conductor of electricity).

The Nitrogen Family–Old Group VA ,new Group 15 • These elements have 5 valence electrons • Include Nitrogen – most abundant gas in the atmosphere • Phosphorus – has allotropes that are Red and White • Bismuth – the metal used in automatic sprinklers because of its low melting point • Arsenic – a poisonous element used in medicine and even rat poison.

Transition Metals – Groups 3 thru 12 • These all vary dramatically in reactivity, Their oxidation states (# of valence electrons) vary. They are a bridge between the very reactive Alkali and Alkaline Earth Metals and the nonmetals.

Most of the elements are Metals • Examples include: Iron, Bismuth, Tin, Sodium, Calcium, Gallium, etc. • Bismuth – used in automatic sprinklers • Gallium - has an oxidation number +3 • Cobalt – A metal w/ more than one oxidation state • Metals tend to form positive (+) ions. • Most Metals form Ionic bonds w/ nonmetals. • Physical Properties • Such as hardness, shiny, malleability (pounded into shapes), • ductility (stretched or pulled into a wire) electrical conductivity and magnetic. • Chemical Properties • Metals show a wide range of chemical properties.

17 Nonmetals • a. There are 17 nonmetals, each are located to the right of the zigzag line in the periodic table. • b. Phosphorus – has Common allotropes of Red & white • c. Selenium – nonmetal that is a “good conductor” • Non metals tend to steal electrons when they form negative (-) ions. • c. Physical Properties – in general, the physical properties of nonmetals are opposite those of metals. Powdery, gaseous, crumbly, non conductive, dull, not ductile or malleable. • d. Chemical properties – usually form ionic bonds when combined w/ metals (NaCl, FeO2, and CaCl2 ) and usually form covalent bonds when combined w/ other nonmetals (CO2, O2, C6H12O6) • Asbestos – substance once used for its fire retardant characteristics but is no longer used because of it’s a carcinogen. • Carbon – the element on which all life is based. • e. Even though Hydrogen (H) is located in Group 1, it is still a nonmetal and exhibits oxidation states of +1 and -1. Nonmetals are the light blue elements

Metalloids • AKA “semi metals” • 7 elements on the zigzag border between metals and the non metals. • Their properties will sometimes make them act like a metal and then sometimes act like a nonmetal. • Most important characteristic is their varying ability to conduct electricity. Silicon is used to make Semiconductors which are used in making computer chips.

“Need-to-Know” Elements Remember: Atomic Mass – # of Protons = # of Neutrons Remember: Atomic # = # of Protons & also # of Electrons

CAR-BON This is the magic element for everything on Earth. All life on Earth depends on carbon (C). It is in nearly every biological compound that makes up our bodies, systems, organs, cells, and organelles. When you breathe out, there is a lot of carbon dioxide (CO2). Carbon has been known and used for thousands of years. It was never really discovered. Ancient people knew of the black soot left over after a fire. That was carbon. Carbon is the sixth element in the periodic table. Located between boron (B) and nitrogen (N), it is a very stable element. Because it is stable, it can be found both by itself and in many naturally occurring compounds. Scientists describe the three states of carbon as diamond, amorphous, and graphite. It is the same graphite you find in pencils. Where can you find carbon? Where do we find elements on the Earth CAR-BON This is the magic element for everything on Earth. All life on Earth depends on carbon (C). It is in nearly every biological compound that makes up our bodies, systems, organs, cells, and organelles. When you breathe out, there is a lot of carbon dioxide (CO2). Carbon has been known and used for thousands of years. It was never really discovered. Ancient people knew of the black soot left over after a fire. That was carbon. Carbon is the sixth element in the periodic table. Located between boron (B) and nitrogen (N), it is a very stable element. Because it is stable, it can be found both by itself and in many naturally occurring compounds. Scientists describe the three states of carbon as diamond, amorphous, and graphite. It is the same graphite you find in pencils.

CAR-BON This is the magic element for everything on Earth. All life on Earth depends on carbon (C). It is in nearly every biological compound that makes up our bodies, systems, organs, cells, and organelles. When you breathe out, there is a lot of carbon dioxide (CO2). Carbon has been known and used for thousands of years. It was never really discovered. Ancient people knew of the black soot left over after a fire. That was carbon. Carbon is the sixth element in the periodic table. Located between boron (B) and nitrogen (N), it is a very stable element. Because it is stable, it can be found both by itself and in many naturally occurring compounds. Scientists describe the three states of carbon as diamond, amorphous, and graphite. It is the same graphite you find in pencils. Where can you find carbon? Carbon

CAR-BON This is the magic element for everything on Earth. All life on Earth depends on carbon (C). It is in nearly every biological compound that makes up our bodies, systems, organs, cells, and organelles. When you breathe out, there is a lot of carbon dioxide (CO2). Carbon has been known and used for thousands of years. It was never really discovered. Ancient people knew of the black soot left over after a fire. That was carbon. Carbon is the sixth element in the periodic table. Located between boron (B) and nitrogen (N), it is a very stable element. Because it is stable, it can be found both by itself and in many naturally occurring compounds. Scientists describe the three states of carbon as diamond, amorphous, and graphite. It is the same graphite you find in pencils. Where can you find carbon? Nitrogen The second of the big three elements in row two is nitrogen (N). Nitrogen is the seventh element of the periodic table. It is located between carbon (C) and oxygen (O). Along with carbon and oxygen, nitrogen is essential in most of the compounds that allow life to exist. It would be great if you remember that nitrogen is an important part of amino acids. We'll tell you again later, but you should always know that almost eighty percent of Earth's atmosphere is made of nitrogen gas. Even though it surrounds us every day, nitrogen wasn't isolated until 1772 by Daniel Rutherford. It was named eighteen years later by the chemist Chaptal. Nitrogen is a clear gas that has no smell when it is in its pure form. It is not very reactive when it is a pure molecule, but it can create very reactive compounds when combined with other elements, including hydrogen (H) in ammonia (NH3).

CAR-BON This is the magic element for everything on Earth. All life on Earth depends on carbon (C). It is in nearly every biological compound that makes up our bodies, systems, organs, cells, and organelles. When you breathe out, there is a lot of carbon dioxide (CO2). Carbon has been known and used for thousands of years. It was never really discovered. Ancient people knew of the black soot left over after a fire. That was carbon. Carbon is the sixth element in the periodic table. Located between boron (B) and nitrogen (N), it is a very stable element. Because it is stable, it can be found both by itself and in many naturally occurring compounds. Scientists describe the three states of carbon as diamond, amorphous, and graphite. It is the same graphite you find in pencils. Where can you find carbon? Where can you find nitrogen? Nitrogen

CAR-BON This is the magic element for everything on Earth. All life on Earth depends on carbon (C). It is in nearly every biological compound that makes up our bodies, systems, organs, cells, and organelles. When you breathe out, there is a lot of carbon dioxide (CO2). Carbon has been known and used for thousands of years. It was never really discovered. Ancient people knew of the black soot left over after a fire. That was carbon. Carbon is the sixth element in the periodic table. Located between boron (B) and nitrogen (N), it is a very stable element. Because it is stable, it can be found both by itself and in many naturally occurring compounds. Scientists describe the three states of carbon as diamond, amorphous, and graphite. It is the same graphite you find in pencils. Where can you find carbon? Oxygenn You're breathing right now and your body is taking in oxygen (O) molecules. You need oxygen to survive, as do almost all other living organisms. It's a good thing that oxygen makes up over twenty percent of the Earth's atmosphere. We are the only planet in the solar system with enough oxygen gas available to let us survive. Did you know that if you breathe too much oxygen you could die? What about this: If you have a room filled with oxygen and hydrogen (H) and someone lights a match... it will explode! That's because oxygen is very reactive. Oxygen is the eighth element of the periodic table and can be found in the second row (period). Alone, oxygen is a colorless and odorless molecule that is a gas at room temperature. Oxygen molecules are not the only form of oxygen in the atmosphere; you will also find oxygen as ozone (O3) and carbon dioxide (CO2). A chemist named Priestly isolated oxygen in 1774.

CAR-BON This is the magic element for everything on Earth. All life on Earth depends on carbon (C). It is in nearly every biological compound that makes up our bodies, systems, organs, cells, and organelles. When you breathe out, there is a lot of carbon dioxide (CO2). Carbon has been known and used for thousands of years. It was never really discovered. Ancient people knew of the black soot left over after a fire. That was carbon. Carbon is the sixth element in the periodic table. Located between boron (B) and nitrogen (N), it is a very stable element. Because it is stable, it can be found both by itself and in many naturally occurring compounds. Scientists describe the three states of carbon as diamond, amorphous, and graphite. It is the same graphite you find in pencils. Where can you find carbon? Oxygen

CAR-BON This is the magic element for everything on Earth. All life on Earth depends on carbon (C). It is in nearly every biological compound that makes up our bodies, systems, organs, cells, and organelles. When you breathe out, there is a lot of carbon dioxide (CO2). Carbon has been known and used for thousands of years. It was never really discovered. Ancient people knew of the black soot left over after a fire. That was carbon. Carbon is the sixth element in the periodic table. Located between boron (B) and nitrogen (N), it is a very stable element. Because it is stable, it can be found both by itself and in many naturally occurring compounds. Scientists describe the three states of carbon as diamond, amorphous, and graphite. It is the same graphite you find in pencils. Where can you find carbon? Fluorine Fluorine (F) is the ninth element of the periodic table and was first isolated and identified in 1886 by a scientist named Moisson. Scientists knew about fluorine for hundreds of years, but it wasn't isolated until the late 1800s. Now we use fluorine in refrigerators, toothpaste, and rocket fuels. Located in the second period of the table (row 2), fluorine is the first element in the family of halogen gases. Fluorine is a yellowish gas at room temperature and is very dangerous. Be careful if you are working in a chemistry lab with fluorine gas. Even though the names rhyme, don't get fluorine mixed up with chlorine (Cl) in your homework. They are very different elements, and fluorine is both poisonous and very reactive with other elements. It can combine with nearly any element on Earth.

CAR-BON This is the magic element for everything on Earth. All life on Earth depends on carbon (C). It is in nearly every biological compound that makes up our bodies, systems, organs, cells, and organelles. When you breathe out, there is a lot of carbon dioxide (CO2). Carbon has been known and used for thousands of years. It was never really discovered. Ancient people knew of the black soot left over after a fire. That was carbon. Carbon is the sixth element in the periodic table. Located between boron (B) and nitrogen (N), it is a very stable element. Because it is stable, it can be found both by itself and in many naturally occurring compounds. Scientists describe the three states of carbon as diamond, amorphous, and graphite. It is the same graphite you find in pencils. Where can you find carbon? Fluorine Rocket FuelFluorine is used in rocket fuels. Fluorine is a very reactive element which makes it good for very explosive reactions. Uranium PurificationFluorine is used to refine another element called uranium. Uranium is used in nuclear reactors for fuel. Without fluorine, scientists couldn't get pure uranium. Refridgeration FluidsThere is something that helps your refrigerator work. It's called Freon. Freon is pumped through a whole system of tubes. As the Freon moves through your refrigerator, it makes everything cold. One of the main elements in Freon is fluorine. ToothpasteAt night when it's time to brush your teeth take a look at your toothpaste. Inside that tube is fluorine. Scientists put very small amounts of fluorine inside your toothpaste to help make your teeth whiter. Etching SolutionsIt's very hard to draw something called etched glass. Have you ever seen a really fancy window? Have you see the foggy white part of the window that makes some kind of pattern? That is etched glass. Artists use fluorine when they do that to the glass. Ask your parents. Maybe you have some of that glass at home!

CAR-BON This is the magic element for everything on Earth. All life on Earth depends on carbon (C). It is in nearly every biological compound that makes up our bodies, systems, organs, cells, and organelles. When you breathe out, there is a lot of carbon dioxide (CO2). Carbon has been known and used for thousands of years. It was never really discovered. Ancient people knew of the black soot left over after a fire. That was carbon. Carbon is the sixth element in the periodic table. Located between boron (B) and nitrogen (N), it is a very stable element. Because it is stable, it can be found both by itself and in many naturally occurring compounds. Scientists describe the three states of carbon as diamond, amorphous, and graphite. It is the same graphite you find in pencils. Where can you find carbon? Sodium As we begin our exploration of the third period (row) of the periodic table, we find the element sodium (Na). Being in the first column, sodium is a member of the alkali metal family with potassium (K) and lithium (Li). Sodium's big claim to fame is that it's one of two elements in your table salt. When bonded to chlorine (Cl), the two elements make sodium chloride (NaCl). Sodium is also used as a salt in many fertilizers. Even though humans have been using sodium for thousands of years, it was not isolated until 1807 by a chemist named Davy. When you purify sodium, you actually wind up with a silvery bright metal that is quite soft and malleable. Sodium is one of the few metals that will float when it is placed in water (H2O). Sodium's atomic mass is less that water's atomic mass of 18 amu.

CAR-BON This is the magic element for everything on Earth. All life on Earth depends on carbon (C). It is in nearly every biological compound that makes up our bodies, systems, organs, cells, and organelles. When you breathe out, there is a lot of carbon dioxide (CO2). Carbon has been known and used for thousands of years. It was never really discovered. Ancient people knew of the black soot left over after a fire. That was carbon. Carbon is the sixth element in the periodic table. Located between boron (B) and nitrogen (N), it is a very stable element. Because it is stable, it can be found both by itself and in many naturally occurring compounds. Scientists describe the three states of carbon as diamond, amorphous, and graphite. It is the same graphite you find in pencils. Where can you find carbon? Sodium Glass ManufacturingSodium is used to make glass. You know that silicon makes up most of glass. In the process of making glass sodium is often used as well. Paper ManufacturingThe next time you write on a piece of paper you should know that sodium is used to make that paper. Paper is originally from trees. Before it gets to you a lot of chemicals are used to get it ready. Sodium is one of the elements used. Table SaltWhen you sit at the table for dinner look for the salt shaker. Sodium and chlorine combine to make salt. If you look at the salt very closely you can see that they make little crystals. Those crystals look like little cubes. The shape is partially because of sodium. Developing SolutionsWhen your parents send their photographs on film to be developed, the company uses different liquids to make the pictures appear. Sodium is in some of those solutions. FertilizerSodium is a very important element in fertilizers. Farmers use a lot of fertilizer to make sure their crops grow well. You parents might even use fertilizers in their garden.

Hydrogen

Helium

Carbon

Nitrogen

Oxygon

Sodium

Neon

Magnesium

Iron

The Periodic Table