Understanding the Periodic Table and Classifying Elements

1. Obj: I will be able to classify elements by their properties.Meaning ~ you will be able to understand how the periodic table is arranged and use the characteristics of elemental families to group elements. • Ready-Reporter>Journals please • Responsible- complete the warm-up • Respectful- Please sit in your assigned seats • Warm-up: Please be ready for notes

2. Periodic Table of Elements

3. Chemistry Joke Two atoms walking down the street run into each other. One says to the other, "Are you all right?" "No, I lost an electron!" "Are you sure?" "Yeah, I'm positive!"

5. chlorine nitrogen silver gold mercury oxygen hydrogen helium sodium niobium neodymium carbon

6. Review: Elements • Aristotle’s theory of Air, Water, Fire, and Earth. • Scientists have identified 90 naturally occurring elements, and created about 28 others.

7. Elements • The elements, alone or in combinations, make up our bodies our world, our sun, and in fact, the entire universe.

8. The most abundant element in the Earth’s crust is oxygen.

9. Matter • All matter is composed of atoms and groups of atoms bonded together, called molecules. • Substances that are made from one type of atom only are called pure substances. • Substances that are made from more than one type of atom bonded together are called compounds. • Compounds that are combined physically, but not chemically, are called mixtures.

10. 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. 

11. Periodic Table • The periodic table organizes the 118 known elements • You can predict the physical and chemical properties of the element. • You can also predict what other elements a particular element will react with chemically.

12. Classifying Elements ?

13. Review: Atomic Mass Unit (AMU) • The unit of measurement for an atom is an AMU. It stands for atomic mass unit. • One AMU is equal to the mass of one proton.

14. Atomic Mass Unit (AMU) • There are 6 X 1023 or 600,000,000,000,000,000,000,000 amus in one gram. • (Remember that electrons are 2000 times smaller than one amu).

15. Key to the Periodic Table • Elements are organized on the table according to their atomic number. • The atomic number refers to how many protons an atom of that element has. • Hydrogen has 1 proton, so it’s atomic number is 1. • No two elements have the same atomic number.

16. What’s in a square? • Different periodic tables can include various bits of information, but usually: • atomic number • symbol • atomic mass • number of valence electrons • state of matter at room temperature.

17. Atomic Number • This refers to how many protons an atom of that element has. • No two elements, have the same number of protons. Bohr Model of Hydrogen Atom Wave Model

18. Atomic Mass • Atomic Mass refers to the “weight” of the atom. • It is derived at by adding the number of protons with the number of neutrons. This is a helium atom He. Its atomic mass is 4 (protons plus neutrons). What is its atomic number?

19. Atomic Mass and Isotopes • Some atoms have more or less neutrons than protons. These are called isotopes. • An atomic mass number with a decimal is the total of the number of protons plus the average number of neutrons.

20. Symbols • All elements have their own unique symbol. • It can consist of a single capital letter, or a capital letter and one or two lower case letters. C Carbon Cu Copper

21. Common Elements and Symbols

22. Valence Electrons • Valence electrons are the electrons in the outer energy level of an atom. • These are the electrons that are transferred or shared when atoms bond together.

24. Electron Count: 2+2+6+2+6+2= 20

25. Electrons & the Periodic Table • Elements are grouped because they have similar properties • In some groups, the elements all have the same number of valence electronsin their atoms

26. Electrons & the Periodic Table • In atoms of elements in Groups 1 & 2, the number of valence electrons matches the group number

27. Electrons & the Periodic Table • In atoms of elements in Groups 13-18, the number of valence electrons is 10 fewer than the group number

28. Electrons & the Periodic Table • Atoms of elements in Groups 3-12, the Transition Metals, do not follow a general rule • In addition, helium atoms only have 2 valence electrons Unit A: Chapter 3

30. Grouping the Elements - Group 1 • Group 1: Alkali Metals- • 1 Valence Electron • All metals except Hydrogen, the Group 1 elements, are the most reactive. Unit A: Chapter 3

31. Grouping the Elements - Group 1 • Group 1: Alkali Metals- • 1 Valence Electron • This means that the atoms of these elements are not stable and will lend valence electrons to other atoms. Unit A: Chapter 3

32. Grouping the Elements - Group 1 • Group 1: Alkali Metals- • 1 Valence Electron • These elements are never found uncombined in nature. Unit A: Chapter 3

33. Grouping the Elements - Group 1 • Alkali Metals • Compounds formed from Alkali metals have many uses for humans • NaCl, or Sodium Chloride, is table salt that is used to season your food • Potassium compounds are found in bananas Unit A: Chapter 3

34. Grouping the Elements - Group 2 • Group 2: Alkaline-Earth Metals- • 2 Valence Electrons • Alkaline-Earth metals are very reactive, but not as reactive as Alkali metals. Unit A: Chapter 3

35. Grouping the Elements - Group 2 • Group 2: Alkaline-Earth Metals- 2 Valence Electrons • This is because it is harder for their atoms to lose 2 valence electrons than for the Alkali metals to lose 1 Unit A: Chapter 3

36. Grouping the Elements - Group 2 • Group 2: Alkaline Earth Metals • Magnesium is mixed with other metals to make rims on cars. • Calcium is an important part of the compound that keeps your bones and teeth healthy. Unit A: Chapter 3

37. Grouping the ElementsGroups 3-12 • Groups 3-12: Transition Metals • Groups 3-12 do not have individual group names. Unit A: Chapter 3

38. Groups 3-12 • The Transition Metals are less reactivethan Groups 1 & 2 because they don’t lose their valence electrons as easily. • Groups 3-12 Unit A: Chapter 3

39. Grouping the Elements • Silver and Gold are Transition Metals. Unit A: Chapter 3

40. Grouping the Elements • Transition Metals • Iron, Cobalt, and Nickel, all Transition Metals, are the only elements known to produce a magnetic field. Unit A: Chapter 3

41. Group 13: Boron Group • The most common element from Group 13 is aluminum. Unit A: Chapter 3

42. Group 14: Carbon Group • The nonmetal Carbon, in Group 14, is often found uncombined in nature. Unit A: Chapter 3

43. Carbon forms both diamonds and charcoal. • Carbon also forms a wide variety of compounds such as proteins, fats, and carbohydrates, all necessary for life on earth. Unit A: Chapter 3

44. Group 15: Nitrogen Group • Nitrogen, a gas at room temperature, makes up about 78% of the air you breathe. Unit A: Chapter 3

45. Group 15 • Nitrogen from the air is combined with Hydrogen to make fertilizer. • Fertilizer helps grow the crops that feed us all. Unit A: Chapter 3

46. Group 16 • Oxygen, in Group 16, makes up about 21% of the air you breathe. • Oxygen is very reactive, combining with many other elements such as iron and carbon. Unit A: Chapter 3

47. Group 16 • Sulfur, another common member of Group 16, is used to make sulfuric acid for car batteries. Unit A: Chapter 3

48. Group 17 Halogens • Halogens are the very reactive nonmetals in Group 17. • They react easily because their atoms only need to gain 1 electron to have a complete set Unit A: Chapter 3

49. Group 18: Noble Gases • Noble gases are unreactive nonmetals in Group 18. • These elements’ atoms have full outermost energy levels, and cannot react with other elements Unit A: Chapter 3

50. Group 18 Noble Gases • Noble gases like neon glow when electrically charged. • Argon in a light bulb keeps the filament from burning out. Unit A: Chapter 3