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The Periodic Table

The Periodic Table. Elements are arranged and identified on the periodic table by the number of protons they have in their nucleus. The atomic number is equal to the number of protons in an element. Quick Review.

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The Periodic Table

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  1. The Periodic Table

  2. Elements are arranged and identified on the periodic table by the number of protons they have in their nucleus. The atomic number is equal to the number of protons in an element.

  3. Quick Review While the total number of electrons is important, it is even more important that you understand how many valenceelectrons an atom has. What are valence electrons?

  4. Quick Review Valence electrons are the electrons in the outer energy level. How many valence electrons do each of the following atoms have? 1 valence electron 2 valence electrons 3 valence electrons

  5. Elements in the same column or group have similar physical and chemicalproperties. This because they all have the same number of valence electrons!

  6. Reading Roman numerals: How many valence electrons do the elements of group 2 have? I = 1 II = 2 III = 3 IV = 4 V = 5 VI = 6 VII = 7 VIII = 8 II = 2 You will ignore the A’s and B’s.

  7. How many valence electrons do the elements of group 17 have? How many valence electrons do the elements of group 14 have? VII = 7 IV = 4

  8. Remember: We can determine the number of valence electrons in the atom of an element by using the Roman numerals on the periodic table. How many valence electrons do the elements of group 16 have? How many valence electrons does phosphorous have? VI = 6 V = 5

  9. Lewis Dot Diagrams: Lewis dot structures show the number of valence electrons in an atom using an atoms symbol surrounded by dots representing the valence electrons. Use the Roman numerals on your periodic table to determine the number of valence electrons for elements below. Decide which Lewis dot diagram is an accurate representation. Which Lewis Dot Diagram below accurately represents hydrogen? H H H

  10. Which Lewis Dot Diagram below accurately represents nitrogen? N N N Which Lewis Dot Diagram below accurately represents carbon? C C C

  11. Which Lewis Dot Diagram below accurately represents boron? B B B Which Lewis Dot Diagram below accurately represents phosphorous? P P P

  12. There are several things you will need to memorize about the periodic table. Find the dark jagged line on the Periodic Table On the left side of this line are all of the metals On the right side of this line are all of the nonmetals

  13. Chemical reactions occur when atoms gain, lose, or share electrons. Metals ________________ electrons. This always gives them a ____ charge. lose or donate + gain Nonmetals _________ electrons. This always gives them a ____ charge. _ Nonmetal can also share electrons with one another, and this is what makes a covalent compound.

  14. You need to understand the pattern of elements gaining and losing electrons on the periodic table. Does NOT gain or lose donate 1 electron gains 1 electrons gains 2 electrons donate 2 electron Think about counting from the outside to the inside!

  15. Metalsloseor donateelectrons and nonmetalsgainelectrons Because of this metals react with nonmetals! +1 -1 sodium sodium chloride chlorine

  16. We can see that it is a 1:1 ratio between sodium and chlorine, but why does it work out that way? Once again, it has to do with the valence electrons! +1 -1 sodium sodium chloride chlorine Since sodium donates 1 electron and chlorine gains 1 electron, they join together in a 1:1 ratio.

  17. This is true for all of the combinations of Group 1 and Group 17 elements! HCl LiF NaBr KF CsI RbCl HBr KCl LiF RbBr KBr NaI LiCl FrCl HF They are all 1:1 ratios!

  18. This is also true between metals that lose 2 valence electrons and the nonmetals that gain 2 valence electrons. +2 -2 magnesium magnesium sulfide sulfide Since magnesium donates 2 electrons and sulfur gains 2 electrons, they join together in a 1:1 ratio.

  19. This is true for all of the combinations of Group 2 and Group 16 elements! BeO MgS SrO BaSe CaTe CaS BeSe MgO SrS BaO MgSe CaO BeS BaTe SrSe They are all 1:1 ratios!

  20. The Periodic Table can be used to determine the charge of all of the principal elements! +1 0 +4 or -4 +2 +3 -3 -2 -1

  21. The elements that lay on either side of the dark, jagged have rather unique properties. Sometimes they act like metals, and sometimes they act like nonmetals. Because of this, they are called Metalloids

  22. The metals in the middle of the periodic table are known as the transition metals. Transition Metals

  23. There are several groups on the periodic table whose name you should have memorized. Group 1 = Alkali Metals Group 2 = Alkaline Earth Metals Group 17 = Halogens Group 18 = Noble Gases Noble Gases Alkali Metals Halogens Alkaline Earth Metals

  24. You also need to know that Iron, Cobalt, and Nickel have special properties such as the ability to be made into magnets. Together, these three elements are known as the . Iron Triad Iron Triad

  25. Which group on the periodic table undergoes the fewest chemical reactions? Group 18 The Noble Gases They are inert gases. This is a chemical property that means they will not react with other substances. Inert means inactive!

  26. Ionic compounds are ALWAYS between a metal and a nonmetal. On the left side of this line are all of the metals On the right side of this line are all of the nonmetals

  27. Covalent compounds are ALWAYS between nonmetals. On the right side of this line are all of the nonmetals

  28. Understanding the previous facts at a conceptual level is critical to your success in chemistry. Using this knowledge, determine the identity of each of the following unknown elements. XCl3 The formula above shows the ratio of an unidentified element, X, to chlorine in a covalent molecule. Which element below is most likely the identity of Element X? A sodium B neon C phosphorous D copper Since it is a covalent molecule, it has to be a nonmetal. It cannot be neon since neon is an inert noble gas that would not react with chlorine.

  29. NaX The formula above shows the ratio of an unidentified element, X, to sodium in an ionic salt. In which group on the periodic table does Element X most likely belong? A Group 1 B Group 2 C Group 17 D Group 18 Since it is an ionicsalt, it has to be a nonmetal since sodium is a metal. It cannot be group 18 since group 18 is the inert noble gases that would not react with sodium.

  30. XF The formula above shows the ratio of an unidentified element, X, to fluorine in an ionic salt. Which group below is most likely the identity of Element X? A sulfur B lithium C arsenic D krypton Since it is an ionicsalt, it has to be a metal since fluorine is a nonmetal.

  31. The Law of Conservation of Mass

  32. According to the Law of Conservation of Mass, the mass of the reactants should equal the mass of the products. Reactant 1 + Reactant 2 Product Which scientist’s results below best support the Law of Conservation of Mass?

  33. Solving for Mass When this concept is shown with a chemical equation, nothingchanges about how it should be solved. Hydrogen + Oxygen Water 16.0 g 128 g ? g 16.0 grams of hydrogen reacts with 128 grams of oxygen. Assuming all of the reactants are used up, how much water will be produced? 16.0 g + 128 g = 144 g

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