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7B16 Periodic Table Elements

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Vocabulary Element: substance that cannot be broken down into other simpler substances. There are ~90 natural elements and 25 man-made Atom: smallest particle of an element, each very different from one element to another. Atomic Number = protons, and place in table Atomic Mass = how much mass the atom has React: when elements combine chemically Compound: substances with 2 or more types of atoms held together by bonds. Periodic: repeating regularly

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H = Hydrogen = Atomic Number 1 Hydrogen is very light weight but flammable.

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Background 2000 years ago Greeks thought everything was made from elements: fire, earth, air and water In the 1600s chemists realized those were not elements like carbon, gold, silver, copper, lead, tin, sulfur, mercury, and iron, all found in nature. The rest were discovered later. But what did they have in common with each other?

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Dmitri Mendeleev Russian scientist who developed the modern Periodic Table with 63 known elements (1869) Collected information on element properties. Grouped elements by their: Atomic mass Physical and Chemical properties He noticed a periodic pattern (periodic means repeating)

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First Periodic Table The 63 elements he knew were NOT the first 63 in the Periodic Table. Some were missing! He put elements into similar groups and left some blanks in the table where he predicted that new elements would be found and placed He even used the patterns in the table to predict the properties of the new elements. Later scientists proved he was right!

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Mendeleevs Table

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Modern Periodic Table

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Modern Periodic Table of Elements Everything is made from only 115 elements. Each element represented by a symbol, either One uppercase letter, like C for carbon, or An uppercase and lowercase, like Cu for copper

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Families or Groups There are several other pieces of information. There are several families or groups: Non-metals Alkali metals Alkaline earth metals Transition metals Rare earth metals Other metals Halogens Noble gases

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Label Your Periodic Table 1.Label the groups (columns) as 1-18 at the top. 2.Label the periods (rows) as 1-7 down the left. 3.Using a dark color, draw a zig-zag diagonal staircase line dividing metals from non-metals. Left of B, between B & Al, between Al & Si, between Si & Ge, between Ge & As, between As & Sb, between Sb & Te, between Te & Po, between Po & At 4.Draw circles around Br (35), Hg (80), and UUB (112). These are liquids at room temperature.

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Color Your Periodic Table Draw & label a Color Key like p. B27 in your textbook. Color each group with its designated color.

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Challenge Question 1 Decide if each element is 1.(Li) lithium 2.(C) carbon 3.(S) sulfur 4.(Ca) calcium 5.(Ti) titanium 6.(Br) bromine a metal or non-metal. 1.Metal 2.Non-metal 3.Non-metal 4.Metal 5.Metal 6.Non-metal

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Solid, Liquid, or Gas Most elements are solid at room temperature. Their symbols are shaded black. The 11 elements that are gases tend to be at the top right corner of the table. Their symbols are shaded white. 3 elements are liquid at room temperature. Their symbols are shaded gray.

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Reactivity React is when elements combine chemically. Elements likely to combine are highly reactive, so they will react with many other substances. The least reactive elements are the noble gases in the far right column. The most reactive metals are in the two columns on the far left. The most reactive non-metals are in the halogen family in column 17.

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Challenge Question 2 Find magnesium on the 1.What is magnesiums chemical symbol? 2.Is magnesium a solid, liquid, or gas? 3.What family does magnesium belong to? 4.Based on its family, do you expect magnesium to be very reactive, not reactive, or somewhat reactive? Periodic Table 1.Mg 2.Solid at room temperature 3.Alkaline earth metals 4.Very reactive

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Forming Compounds Elements contain only one type of atom. Compounds contain two or more types of atoms held together by chemical bonds. Water forms when hydrogen and oxygen react The 115 elements form millions of compounds This is similar to how many words in the dictionary are formed from just 26 letters. Compounds and their elements have different properties. H 2 O is different than elements H or O.

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Chemical Names Compound names often identify the elements Table salt is called sodium chloride, so its name says it contains sodium and chlorine. Notice the ending is changed from chlorine to chloride in the compound name.

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Chemical Formulas Chemical formulas are a short way to identify the kind and number of atoms in a compound. Na=sodium, Cl=chlorine, so table salt formula is NaCl=sodium chloride Water is made of two hydrogen atoms bonded to one oxygen atom. H = hydrogen, O = oxygen, so water = H 2 O The 2 means 2 hydrogens. No number means 1.

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Challenge Question 3 The chemical formula for 1.What elements are in baking soda? 2.How many of each kind of atom is represented by the formula for baking soda? baking soda is NaHCO 3 1.Na=sodium, H=hydrogen, C=carbon, O=oxygen 2.One Na sodium, one H hydrogen, one C carbon, and three O oxygens

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Classifying Matter Everything around you is either an element, a compound, or a mixture of both. Helium balloons & copper in pennies=elements Water, salt, sugar, protein and fat=compounds Air is a mixture since it contains elements like oxygen and nitrogen, and compounds like carbon dioxide and water.

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7B16 Periodic Table Analysis pB30 On another paper copy & explain in 1 paragraph 2) Sodium and chlorine form sodium chloride, or table salt. Is table salt an element or compound? 3) Is seawater an element, compound, or mixture? Give examples and explain. 4) Explain the relationship between an atom and a compound.