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Atoms pp.32-37

Atoms pp.32-37. The Rutherford model of the atom (1911). Atoms. Matter – Anything that has mass , takes up space ( volume ) and has some sort of atomic structure. Atoms. Atoms – are the smallest, simplest fundamental units of matter. The building blocks of matter.

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Atoms pp.32-37

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  1. Atoms pp.32-37 The Rutherford model of the atom (1911)

  2. Atoms • Matter–Anything that has mass, takes up space (volume) and has some sort of atomic structure.

  3. Atoms • Atoms – are the smallest, simplest fundamental units of matter. • The building blocks of matter. • Atoms are composed of 3 subatomic particles: • Protons, Neutrons, Electrons

  4. Atoms • Elements – are matter that is composed (made up of) only one type of atom. • A pure substance (like Au, Ag, Pt, Cu or Al) • Your bling is NOT an element

  5. Periodic Table of the Elements Insert periodic table here

  6. PERIODIC TABLEP. 712 • The periodic table is an organized listing of all known types of elements. Name of element Hydrogen Atomic Number 1 H Chemical symbol Atomic Mass (weight) 1.008

  7. PERIODIC TABLE P. 712 The first 92 elements are naturally occurring, meaning they are found on earth and are NOT man made. All the rest are made in a lab or nuclear reactor. Name of element Calcium Atomic Number 20 Ca Chemical symbol Atomic Mass (weight) 40.078

  8. Atomic Mass (Mass Number) • The atomic mass of an atom is equal to the sum of its protons and neutrons. • Atomic mass is also known as mass number or atomic weight. • Mass is expressed in units called AMU’s (Atomic Mass Units)

  9. Atomic Number • The atomic number is equal to the number of protons in the atom’s nucleus. • Remember the number of protons tells you which atom/element you have.

  10. 1 1.0079 H Hydrogen Atomic Mass - Atomic # = # NEUTRONS • ATOMIC mass minus the ATOMIC NUMBER equals the number of NEUTRONS in the nucleus What does the nucleus of hydrogen have in it ?

  11. C Mass Number Average atomic mass 12 6 Atomic Number Atomic Number Periodic Table - Atomic Symbols • Information on an element is noted in different ways in different texts and periodic tables. 6 C 12.01

  12. PERIODIC TABLE P. 712 8 3 4 5 6 7 Transition Metals = almost all have 2 valence e-

  13. Periodic Table P. 712

  14. Periodic Table P. 712 • Los Alamos National Lab Interactive Periodic Table

  15. Model of an atom • Atoms are too small to see even with a microscope. So we use models! • A cubic centimeter of air has 45 billion billion atoms in it. That’s 45 with 18 zeros after it. • Another Example: Take a millimeter, divide into 1000 equal widths (called microns). • Now take one of those microns and divide it into 10,000 equal pieces. (one ten-millionth of a millimeter). • That is how small an atom is!!!!!!

  16. Bohr Model of the Atom (1913) (1904) Dalton’s Model of the Atom (1803) The Modern Model of the Atom (Schroedinger 1926) Rutherford Atomic Model (1911) The Model of the Atom

  17. Parts of the atom P. 35 Electrons Protons Neutrons

  18. Model of an atom • Atoms are mostly EMPTY space.

  19. Model of an atom • Protons and neutrons are found INSIDE the nucleus, and electrons are found as a cloud outside the nucleus.

  20. P PROTONS • PROTONS – are subatomic particles found in the nucleus of the atom. • have a mass of 1.0 Atomic Mass Unit – let’s just call it 1.0 amu. • have a positive electrical chargeof +1. • The number of protons determines the atom’s identity. • The nucleus is positively charged.

  21. N NEUTRONS • NEUTRONS – are subatomic particles found inside the nucleus. • have a mass of slightly more than 1.0 amu. • Have anelectrical chargeof zero – thus they are neutral (hence the name). • The atomic mass of an atom is the number of protons + neutrons inside its nucleus. • If an atom has more or less neutrons than it normally should have, we call it an ISOTOPE. • Carbon-14 is an isotope of carbon, is radioactive and is used to date fossils (like Mr, Mauer). More later.

  22. e ELECTRONS • Subatomic particles found in electron shells or orbitals OUTSIDE the nucleus. • An electrons Mass is very tiny - let’s just call it zero (0). • Electrical charge is -1 (exactly opposite of the protons).

  23. ELECTRONS • Electrons determine the chemical properties of an atom. (how it reacts/behaves around other atoms). • Have potential energy. • The farther away from nucleus, the more energy they have. • Can change energy levels/shells/orbitals

  24. ELECTRONS • Atoms normally have a zero net charge overall. • That means the number of protons(+) in an atom equals the number of electrons(-). • Sometimes atoms may lose or gain electrons and become electrically charged atoms called IONS.

  25. Subatomic Particles(parts of the atom) 1 amu (atomic mass unit) is defined as 1/12 the mass of the carbon atom with 6 protons and 6 neutrons. 1 amu = 1.7 X 10-24 g (0.0000000000000000000000017 g)

  26. ISOTOPES • ISOTOPESare atoms of the same element which have different atomic weights because they have different numbers of neutrons. • For instance • Carbon normally has 6 protons, atomic mass of 12. (C-12) • Carbon can also have atomic mass of 13 (C-13). • Carbon also exists with atomic mass of 14 (C-14). • Differences due to number of neutrons, not protons

  27. Understanding Atoms This diagram shows how to draw electrons for each energy level of an atom. A scientist named Neils Bohr created this representation.

  28. Atomic Mass • Atomic Number • All atoms are usually neutrally charged Max. 32 Max. 18 Max. 8 Max. 2 1st energy level 2nd energy level 3rd energy level 4th energy level

  29. ELECTRON Energy Levels (Shells/Orbitals) • The first electron shell is full with 2 ELECTRONS • The second shell is full with 8 ELECTRONS • The third shell is full with 18 ELECTRONS. • The fourth shell is full with 32 ELECTRONS. • Electrons in the outermost shell are called VALENCE ELECTRONS. • These electrons are reactive and are involved in bonding to other atoms (when the shell is not full!) • 2, 8 , 18, 32, 32, 18, 8

  30. ON THE TEST???? • Be prepared to answer questions about the first 20 elements • Examples: atomic number, atomic mass, electron configurations, valance electrons, etc.

  31. WHY LEARN JUST THE FIRST 20? • Living things are composed of simple, common atoms... • NOT the big, rare fancy atoms .... • In fact about 95 percent of your body is composed of just 6 common atoms .... • CHNOPS - Remember these! • CARBON, HYDROGEN, NITROGEN, OXYGEN, PHOSPHORUS AND SULFUR

  32. P - e WHAT DOES HYDROGEN LOOK LIKE ? Atomic Number = 1 Atomic Mass Number = 1 Electrical Charge = neutral + E

  33. 2 4.0026 He Helium HELIUM Can you draw this Bohr Model ?

  34. N P P N - - e e THE BOHR MODEL FOR HELIUM Atomic Number = 2 Atomic Mass Number = 4 Electrical Charge = neutral 0 + + 0

  35. 3 6.941 Li Lithium LITHIUM

  36. P e e N - e THE LITHIUM MODEL Atomic Number = 3 Atomic Mass Number = 7 Electrical Charge = neutral - + 3 - 0 4 THE FIRST SHELL IS FULL WITH TWO ELECTRONS

  37. 6 12.011 C Carbon CARBON

  38. P N - - - - - - e e e e e e THE CARBON MODEL Atomic Number = 6 Atomic Mass Number = 12 Electrical Charge = neutral + 6 0 6

  39. 11 22.989 Na Sodium SODIUM

  40. P E E N E THE SODIUM MODEL Atomic Number = 11 Atomic Mass Number = 23 Electrical Charge = neutral 11 2 1 12 8

  41. 19 39.102 K Potassium POTASSIUM

  42. E P E N E THE POTASSIUM MODEL Atomic Number = 19 Atomic Mass Number = 39 Electrical Charge = neutral 19 2 9 20 8

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