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Atomic Structure and the Periodic Table

Atomic Structure and the Periodic Table. Early Models of the Atom. Dalton’s Atomic Theory - All elements are composed of atoms - All atoms of a given element are identical - Atoms of different elements are different - Compounds consist of the atoms of different elements

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Atomic Structure and the Periodic Table

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  1. Atomic Structure and the Periodic Table

  2. Early Models of the Atom Dalton’s Atomic Theory - All elements are composed of atoms - All atoms of a given element are identical - Atoms of different elements are different - Compounds consist of the atoms of different elements - Atoms are not created or destroyed in a chemical change

  3. Structure of the Nuclear Atom Thomson’s experiment- showed that atoms contained electrons

  4. Thomson’s Cathode Ray Tube

  5. Plum Pudding Model

  6. Structure of the Nuclear Atom • Electron- negatively charged subatomic particle • Proton- positively charged subatomic particle found in the nucleus of the atom • Neutron- a subatomic particle with no charge that is found in the nucleus

  7. Atomic Structure

  8. Structure of the Nuclear Atom • Rutherford’s Experiment- showed that atoms have a dense nucleus

  9. Rutherford’s Model

  10. Atomic Structure • Nucleus – • very dense (contains nearly all the mass of the atom yet occupies a very small space) • location of positively charged protonsand neutral neutrons • Electron Cloud – • space surrounding the nucleus • location of negatively charged electrons

  11. Subatomic Particles

  12. Bohr Model of theAtom Determined that electrons orbit the nucleus in specific energy levels

  13. Bohr Model

  14. The # of protons = atomic number • The number of protons determines theelement.All atoms of the same element have the same # of protons. • Count the protons and use the atomic number on the periodic table to identify the element.

  15. The # of protons = atomic number Identify the element… Let's Count - 2 3 4 1 5 6 7 NITROGEN! 7 protons, so…

  16. Distinguishing Between Atoms Practice- How many protons and electrons are in each atom? • Fluorine • Aluminum • calcium

  17. Mass number = # of protons + # of neutrons Find the mass number… Let's Count - 2 3 4 8 9 11 10 14 13 12 1 7 6 5 14 So the mass number is…

  18. Distinguishing Between Atoms Practice- How many protons, electrons and neutrons are in the following atoms? Atomic Number Mass Number • Beryllium 4 9 • Neon 10 20 • Sodium 11 23

  19. Mass number – atomic number = neutrons Practice- How many neutrons are in each atom? • 168 O • 10847 Ag • 20782 Pb

  20. Practice Questions: • Use the information below to answer the questions that follow. • What is the name of this element? • What is the mass number of this element? A certain element has a nucleus containing eight protons and ten neutrons and has ten electrons orbiting the nucleus. Oxygen 18

  21. Distinguishing Between Atoms Isotopes- atoms with the same number of protons but different number of neutrons What is the difference? Protons + Neutron = Atomic Mass If the number of protons never changes than it’s the number of neutrons!!!

  22. The picture shows a model of the element – • Fluorine • Carbon • Beryllium • Oxygen

  23. Label each part of the diagram above. • W – Nucleus • X – Neutron • Y – Proton • Z – Electron

  24. Distinguishing Between Atoms • Atomic mass- the weighted average of the masses of the isotopes of an element - Atomic mass unit- a unit of mass equal to one-twelfth the mass of carbon twelve atom

  25. Practice- The three isotopes of chromium are chromium-50, chromium-52, and chromium 53. How many neutrons are in each isotope, given that chromium always has an atomic number of 24?

  26. Calculating average atomic mass Average atomic mass = (fractional abundance of isotope 1)(mass of isotope 1) + (fractional abundance of isotope 2)(mass of isotope 2) Practice 1. Calculate the atomic mass of bromine. The two isotopes of bromine have atomic masses and relative abundances of 78.92 amu (50.69%) and 80.92 (49.31%)

  27. Practice 2- Element X has two natural isotopes. The isotope with a mass of 10.012 has a relative abundance of 19.91%. The isotope with a mass of 11.009 has a relative abundance of 80.09%. Calculate the atomic mass of this element. Practice 3- Calculate the percent abundance of copper-63 if the atomic mass is 63.546 and the exact masses of the isotopes are 64.93 amu and 62.93 amu.

  28. The Periodic Table of Elements

  29. The Periodic Table • Mendeleev- arranged the elements by increasing atomic mass

  30. The Modern Periodic Table- shows all the known elements in order of increasing atomic number

  31. Group –elements located in the same column. What do these have in common? Some Examples Period – elements in the same row.

  32. The periodic table is organized to group elements with similar properties in vertical columns

  33. Group A - Representative Elements Group B - Transition Metals

  34. Iodine Sulfur NONMETALS • gain electrons to become negative ions • dull • brittle • poor conductors of heat and electricity • usually gases at room temperature

  35. METALS • lose electrons to become positive ions • shiny • malleable • ductile • good conductors of heat and electricity • usually solids at room temperature

  36. METALS NONMETALS METALLOIDS Right of the staircase On the staircase Left of the staircase

  37. The Modern Periodic Table • Metals- elements on the left side of the table - alkali metals- metals in group 1A - alkaline earth metals- metals in group 2A - transition and inner transition metals- group B, located in the center of the table Metalloids- have properties intermediate to metals and nonmetals Nonmetals- elements on the right side of the table - halogens- nonmetals in group 7A - noble gases- elements in group 0

  38. Natural States of the ElementsDiatomic Elements

  39. BrINClHOF Elements- diatomic

  40. The Modern Periodic Table • Periods- horizontal rows on the periodic table • Periodic law- when elements are arranged by increasing atomic number, there are periodic or repeating properties • Groups (families)- columns on the periodic table - Group A elements- representative elements - Group B elements- transition metals

  41. Practice Questions: • Which of the following groups contains members with similar chemical activity? • Li, Be, C • Be, Mg, Sr • Sc, Y, Zr • C, N, O

  42. Which of the following elements is rarely involved in bonding because it is already stable? • Ca • O • Ar • Cl

  43. Elements in Group 16 of the periodic table usually – • form large molecules • gain electrons when bonding • act like metals • solidify at room temperature

  44. A new element is discovered. It can be hammered flat into sheets and made into wire. The element is most likely – • a metal • hydrogen • a nonmetal • a metalloid

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