Chapter 17: Properties of Atoms and the Periodic Table

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2. Table of Contents 17 Unit 4: The Nature of Matter Chapter 17: Properties of Atoms and the Periodic Table 17.1: Structure of the Atom 17.2: Masses of Atoms 17.3: The Periodic Table

3. Structure of the Atom 17.1 Scientific Shorthand • Scientists have developed their own shorthand for dealing with long, complicated names. • Chemical symbols consist of one capital letter or a capital letter plus one or two smaller letters.

4. AN ELEMENT IS A SUBSTANCE IN WHICH ALL OF THE ATOMS ARE THE SAME. ALL ELEMENTS ARE LISTED IN THE “PERIODIC TABLE”, AN ORGANIZED LIST OF ALL KNOWN ELEMENTS. ELEMENTS

5. SOME SYMBOLS OF ELEMENTS ARE EASY TO REMEMBER BECAUSE THEY ARE THE FIRST (and sometimes second) LETTER OF THE ELEMENTS NAME. Examples: C = Carbon O = Oxygen He = Helium (If a 2nd letter is used, it is ALWAYS lower-case.) ELEMENTS

6. SOME SYMBOLS OF THE ELEMENTS DON’T MATCH UP AT ALL. EXAMPLES: Ag = Silver Au = gold Fe = Iron K = Potassium Pb = Lead THE REASON FOR THIS IS THE FIRST LETTER OR 2 COMES FROM THAT ELEMENTS “LATIN” NAME. ELEMENTS

7. SODIUM Na MAGNESIUM Mg CHLORINE Cl ALUMINUM Al COPPER Cu ZINC Zn MERCURY Hg HYDROGEN H ELEMENTS

8. Structure of the Atom 17.1 Scientific Shorthand • For some elements, the symbol is the first letter of the element's name. • For other elements, the symbol is the first letter of the name plus another letter from its name. • Because scientists worldwide use this system, everyone understands what the symbols mean.

9. Structure of the Atom 17.1 Atomic Components • An element is matter that is composed of one type of atom, which is the smallest piece of matter that still retains the property of the element. • Atoms are composed of particles called protons, neutrons, and electrons. Click image to view movie

10. Structure of the Atom 17.1 Atomic Components • Protons and neutrons are found in a small positively charged center of the atom called the nucleusthat is surrounded by a cloud containing electrons. • Protons are particles with an electrical charge of 1+.

11. Structure of the Atom 17.1 Atomic Components • Electrons are particles with an electrical charge of 1–. • Neutrons are neutral particles that do not have an electrical charge.

12. Structure of the Atom 17.1 Quarks—Even Smaller Particles • Protons and neutrons are made up of smaller particles called quarks. • So far, scientists have confirmed the existence of six uniquely different quarks.

13. Structure of the Atom 17.1 Quarks—Even Smaller Particles • Scientists theorize that an arrangement of three quarks held together with the strong nuclear force produces a proton. • Another arrangement of three quarks produces a neutron

14. Structure of the Atom 17.1 Finding Quarks • To study quarks, scientists accelerate charge particles to tremendous speeds and then force them to collide with—or smash into—protons. This collision causes the proton to break apart. • The particles that result from the collision can be detected by various collection devises.

15. Structure of the Atom 17.1 The Sixth Quark • Scientists found five quarks and hypothesized that a sixth quark existed. However, it took a team of nearly 450 scientists from around the world several years to find the sixth quark. • The tracks of the sixth quark were hard to detect because only about one billionth of a percent of the proton collisions performed shows a presence of a sixth quark.

17. Structure of the Atom 17.1 Models—Tools for Scientists • Scientists and engineers use models to represent things that are difficult to visualize—or picture in your mind. • Scaled-down models allow you to see either something too large to see all at once, or something that has not been built yet. • Scaled-up models are often used to visualize things that are too small to see.

18. Structure of the Atom 17.1 Models—Tools for Scientists • To study the atom, scientists have developed scaled-up models that they can use to visualize how the atom is constructed. • For the model to be useful, it must support all of the information that is known about matter and the behavior of atoms.

19. Structure of the Atom 17.1 The Changing Atomic Model • In the 1800s, John Dalton, an English scientist, was able to offer proof that atoms exist. • Another famous Greek philosopher, Aristotle, disputed Democritus's theory and proposed that matter was uniform throughout and was not composed of smaller particles.

20. Structure of the Atom 17.1 The Changing Atomic Model • In the 1800s, John Dalton, an English scientist, was able to offer proof that atoms exist. • Dalton's model of the atom, a solid sphere was an early model of the atom. • The model has changed somewhat over time.

21. Structure of the Atom 17.1 The Electron Cloud Model • By 1926, scientists had developed the electron cloud model of the atom that is in use today. • An electron cloud is the area around the nucleus of an atom where its electrons are most likely found.

22. Structure of the Atom 17.1 The Electron Cloud Model • The electron cloud is 100,000 times larger than the diameter of the nucleus. • In contrast, each electron in the cloud is much smaller than a single proton. • Because an electron's mass is small and the electron is moving so quickly around the nucleus, it is impossible to describe its exact location in an atom.

23. Section Check 17.1 Question 1 Which is the smallest piece of matter that still retains the property of the element? A. atom B. quark C. neutron D. proton

24. Section Check 17.1 Answer The answer is A. An atom is the smallest piece of matter that still retains the property of the element.

25. Section Check 17.1 Question 2 What particles are found in the nucleus of an atom? A. protons and electrons B. protons and neutrons C. neutrons and electrons D. quarks and electrons

26. Section Check 17.1 Answer The answer is B. Electrons are located in an electron cloud surrounding the nucleus of the atom.

27. Section Check 17.1 Question 3 What is the name of the small particles that make up protons and neutrons? Answer Protons and neutrons are made of smaller particles called quarks.

28. Masses of Atoms 17.2 Atomic Mass

29. Masses of Atoms 17.2 Protons Identify the Element • The number of protons tells you what type of atom you have and vice versa. For example, every carbon atom has six protons. Also, all atoms with six protons are carbon atoms. • The number of protons in an atom is equal to a number called the atomic number.

30. Masses of Atoms 17.2 Mass Number • The mass number of an atom is the sum of the number of protons and the number of neutrons in the nucleus of an atom.

31. Masses of Atoms 17.2 Mass Number • If you know the mass number and the atomic number of an atom, you can calculate the number of neutrons. number of neutrons = mass number – atomic number

32. Masses of Atoms 17.2 Isotopes • Not all the atoms of an element have the same number of neutrons. • Atoms of the same element that have different numbers of neutrons are called isotopes.

33. Masses of Atoms 17.2 Identifying Isotopes • Models of two isotopes of boron are shown. Because the numbers of neutrons in the isotopes are different, the mass numbers are also different. • You use the name of the element followed by the mass number of the isotope to identify each isotope: boron-10 and boron-11.

34. Section Check 17.2 Question 1 How is the atomic number of an element determined? Answer The atomic number of an element is equal to the number of protons in an atom of that element.

35. Section Check 17.2 Question 2 The element helium has a mass number of 4 and atomic number of 2. How many neutrons are in the nucleus of a helium atom?

36. Section Check 17.2 Answer Recall that the atomic number is equal to the number of protons in the nucleus. Since the mass number is 4 and the atomic number is 2, there must be 2 neutrons in the nucleus of a helium atom.

37. Section Check 17.2 Question 3 How much of the mass of an atom is contained in an electron? Answer The electron’s mass is so small that it is considered negligible when finding the mass of an atom.

38. End of Chapter Summary File

39. 1. Al A. Albin B. Aluminum C. Alum D. Alco 2. Ca A. Calcium B. Copper C. Camic D.Calco 3. C A.Calcium B. Copper C.Calco D.Carbon ESS 5.8.1 – 5.8.5 TEST

40. 4. Cl • A. CALCIUM B. COPPER C. CHLORINE D. CLOMIDE • 5. Au • SILVER B. GOLD C. LEAD D. AUGMITE • 6. H • HELIUM B. ZINC C. HEAVESTONE D. HYDROGEN • 7. Fe • A. FERRON B. IRON C. IODINE D. FERDROW

41. 8. K • A. POTASSIUM B. KEROTENE C. KELP D. SILVER • 9. Na • NALBINE B. SODIUM C. NITROGEN D. CHLORINE • 10. Hg • HYDROGEN B. HEGLIN C. MERCURY D. SILVER • 11. N • A. NEON B. SODIUM C. TIN D. NITROGEN

42. 12. He • HELIUM B. HYDROGEN C. SILICON D. HEDRIUM • 13. O • OSMIUM B. CARBON C. OXYGEN D. COBALT • 14. Pb • SILVER B. GOLD C. TIN D. LEAD • 15. Ag • A. SILVER B. GOLD C. TIN D. LEAD

43. 16. Zn • TIN B. GOLD C. ZINC D. ZIRCON • 17. Cu • CUPPRO B. CALCIUM C. CARBON D. COPPER • 18. Mg • A. MANGANESE B. MAGNESIUM C.MOLIG D. SODIUM

44. 19. SMALLEST PARTS OF MATTER THAT STILL RETAINS THE PROPERTY OF THE ELEMENT. • CELL B. PROTON C. ELECTRON D. ATOM • 20. ATOMIC PARTICLES WITH A POSITIVE CHARGE. • ATOM B. NEUTRON C. ELECTRON D. PROTON • 21. CENTER OF THE ATOM. • NUCLEUS B. PROTON C. ELECTRON D. NEUTRON • 22. WHERE ARE ELECTRONS LOCATED? • PROTON CLOUD B. ELECTRON CLOUD • C. NUCLEUS D. NEUTRON CLOUD

45. 23. ATOMIC PARTICLES WITH A NEGATIVE CHARGE. • A. PROTONS B. NEUTRONS C. ELECTRONS D. ATOMS • 24. ATOMIC PARTICLES WITH NO CHARGE. • PROTONS B. NEUTRONS C. ELECTRONS D. ATOMS • 25. WHAT IS LOCATED IN THE NUCLEUS? • ELECTRONS AND PROTONS B. ELECTRONS AND NEUTRONS C. PLUTRONS AND NEUTRONS. D. PROTONS AND NEUTRONS.

46. 26. PROTONS AND NEUTRONS ARE MADE UP OF SMALLER PARTICLES CALLED ________. • QUACKS B. QUIRKS C. QUARKS D. QUARTS • 27. SCIENTISTS AND ENGINEERS USE _____ TO REPRESENT THINGS THAT ARE DIFFICULT TO VISUALIZE. • MODELS B. MODEMS C. HAMMERS D. ATOMS • 28. WHAT IS CARBON’S MASS NUMBER? • A. 6 B. 18 C. 12 D. 9

47. 29. SODIUM HAS 11 PROTONS, 12 NEUTRONS; WHAT IS IT’S ATOMIC NUMBER? • 23 B. 12 C. 11 D. 1 • 30. WHAT IS SODIUM’S MASS NUMBER? • A. 23 B. 12 C. 11 D. 1