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Periodic Table of Elements chlorine nitrogen gold silver mercury oxygen hydrogen helium sodium niobium neodymium carbon Elements Science has come along way since Aristotle’s theory of Air, Water, Fire, and Earth. Scientists have identified 90 naturally occurring elements, and created about 28 others. Periodic Table The periodic table organizes the elements in a particular way. A great deal of information about an element can be gathered from its position in the period table. For example, you can predict with reasonably good accuracy the physical and chemical properties of the element. You can also predict what other elements a particular element will react with chemically. Understanding the organization and plan of the periodic table will help you obtain basic information about each of the 118 known elements. Mendeleev In 1869, Dmitri Ivanovitch Mendeléev created the first accepted version of the periodic table. He grouped elements according to their atomic mass, and as he did, he found that the families had similar chemical properties. Blank spaces were left open to add the new elements he predicted would occur. In 1869 Mendeleev and Lothar Meyer (Germany) published nearly identical classification schemes for elements known to date. The periodic table is base on the similarity of properties and reactivities exhibited by certain elements. Later, Henri Moseley ( England,1887-1915) established that each elements has a unique atomic number, which is how the current periodic table is organized. Properties of Metals Metals are good conductors of heat and electricity. Metals are shiny. Metals are ductile (can be stretched into thin wires). Metals are malleable (can be pounded into thin sheets). A chemical property of metal is its reaction with water which results in corrosion. Properties of Non-Metals Sulfur Non-metals are poor conductors of heat and electricity. Non-metals are not ductile or malleable. Solid non-metals are brittle and break easily. They are dull. Many non-metals are gases. Properties of Metalloids Silicon Metalloids (metal-like) have properties of both metals and non-metals. They are solids that can be shiny or dull. They conduct heat and electricity better than nonmetals but not as well as metals. They are ductile and malleable. Families Columns of elements are called groups or families. Elements in each family have similar but not identical properties. For example, lithium (Li), sodium (Na), potassium (K), and other members of family IA are all soft, white, shiny metals. Periods Each horizontal row of elements is called a period. The elements in a period are not alike in properties. In fact, the properties change greatly across even given row. Families on the Periodic Table Elements on the periodic table can be grouped into families (also known as groups or columns) bases on their chemical properties. Each family has a specific name to differentiate it from the other families in the periodic table. Elements in each family react differently with other elements. ALKALI METALS Group 1 Hydrogen is not a member, it is a non-metal Soft and silvery metals Very reactive, esp. with water Conduct electricity Alkali Metals The alkali family is found in the first column of the periodic table. They are shiny, have the consistency of clay, and are easily cut with a knife. Alkali Metals They are the most reactive metals. They react violently with water. Alkali metals are never found as free elements in nature. They are always bonded with another element. Alkaline Earth Metals They are never found uncombined in nature. They have two valence electrons. Alkaline earth metals include magnesium and calcium, among others. ALKALINE EARTH METALS Group 2 White and malleable Reactive, but less than Alkali metals Conduct electricity TRANSITION METALS Groups 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. Transition Metals Transition Elements include those elements in the B families. These are the metals you are probably most familiar: copper, tin, zinc, iron, nickel, gold, and silver. They are good conductors of heat and electricity. Transition Metals The compounds of transition metals are usually brightly colored and are often used to color paints. Boron Family The Boron Family is named after the first element in the family. This family includes a metalloid (boron), and the rest are metals. This family includes the most abundant metal in the earth’s crust (aluminum). BORON FAMILY Group 3 Most are metals Boron is a metalloid Carbon Family This family includes a non-metal (carbon), metalloids, and metals. The element carbon is called the “basis of life.” There is an entire branch of chemistry devoted to carbon compounds called organic chemistry. CARBON FAMILY Group 4 Contains metals, metalloids, and a nonmetal Carbon (C) Nitrogen Family The nitrogen family is named after the element that makes up 78% of our atmosphere. This family includes nonmetals, metalloids, and metals. Other elements in this family are phosphorus, arsenic, antimony, and bismuth. NITROGEN FAMILY Group 5 Can share electrons to form compounds Contains metals, metalloids, and nonmetals Oxygen Family Most elements in this family share electrons when forming compounds. Oxygen is the most abundant element in the earth’s crust. It is extremely active and combines with almost all elements. OXYGEN FAMILY Group 6 Contains metals, metalloids, and nonmetals Reactive Halogen Family The elements in this family are fluorine, chlorine, bromine, iodine, and astatine. Halogens are the most active non-metals. They are never found free in nature. Halogens Group 7 Used as disinfectants All are nonmetals Very reactive are often bonded with elements from Group 1 Noble Gases Noble Gases are colorless gases that are extremely unreactive. One important property of the noble gases is their inactivity. They are inactive because their outermost energy level is full. Because they do not readily combine with other elements to form compounds, the noble gases are called inert. The family of noble gases includes helium, neon, argon, krypton, xenon, and radon. All the noble gases are found in small amounts in the earth's atmosphere. Noble Gases Group 8 Exist as gases Non-metals Not reactive with other elements Rare Earth Elements The thirty rare earth elements are composed of the lanthanide and actinide series. One element of the lanthanide series and most of the elements in the actinide series are called trans-uranium, which means synthetic or man-made. Rare Earth Metals Some are Radioactive The rare earths are silver, silverywhite, or gray metals. Conduct electricity Periods •Each row is called a “period” or “series” •The period or row number tells you how many energy levels an atom has - Group Groups Group 8 = 8 electrons 1 = 1 electron Group Except for He, it has 2 electrons 2 = 2 electrons •Each column is called a “group” •The group number tells us the number of electrons an atom has in its outermost energy level - •The electrons in the outer energy level are called “valence electrons” Transition Metals • How many valence electrons do the transition metals have? Determine the number of energy levels and the number of valence electrons for: 2nd Period = 2 shells 4th Group = 4 valence electrons Determine the number of energy levels and the number of valence electrons for: 3rd Period = 3 shells 1st Group = 1 valence electron Name the element. Number of energy levels ? Valence electrons ? Name the element. Number of energy levels ? Valence electrons ? Neon 2nd Period = 2 energy levels 8th Group = 8 valence electrons Name the element. Number of shells ? Valence electrons ? Name the element. Number of energy levels ? Valence electrons ? Hydrogen 1st Period = 1 energy level 1st Group = 1 valence electron Name the element. Number of shells ? Valence electrons ? Potassium 4th 1st Period = 4 shells Group = 1 valence electron