1. S.MORRIS 2006

2. Bill Nye the Science Guy http://www.youtube.com/watch?v=uZ6zR 0vu7cU&feature=related http://www.youtube.com/watch?v=uZ6zR 0vu7cU&feature=related

3. The Atom The word atom is derived from the Greek word atom which means indivisible. (uncuttable) The Greeks concluded that matter could be broken down into particles too small to be seen. These particles were called atoms

4. The Atom Atoms are made up of 3 types of particles electrons, protons and neutrons. Electrons are tiny, very light particles that have a negative electrical charge (-). Protons are much larger and have a positive charge (+). Neutrons are large and heavy like protons, however neutrons have no electrical charge. (Neutral)

5. ATOMIC STRUCTURE the number of protons in an atom the number of protons and neutrons in an atom He 2 4 Atomic mass Atomic number number of electrons = number of protons

6. The Atom Atomic mass = protons + neutrons Atomic number = the number of protons The number of protons = The number of electrons.

7. Checking on the Atom Give the symbol and number of protons in one atom of: Lithium __________________ Bromine __________________ Iron __________________ Copper __________________ Li, 3 Br, 35 Fe, 26 Cu, 29

8. Checking on the Atom Give the symbol and number of electrons in a neutral atom of: Uranium __________________ Chlorine __________________ Boron __________________ Iodine __________________ U, 92 Cl, 17 B, 5 I, 53

9. Checking on the Atom Give the symbol and number of neutrons in a neutral atom of: Carbon __________________ Copper__________________ Fluorine __________________ Magnesium __________________ C, 12 - 6 = 6 neutrons Cu, 64 - 29 = 35 neutrons Atomic mass = protons + neutrons F, 19 - 9 = 10 neutrons Mg, 24 - 12 = 12 neutrons

10. 1913 Niels Bohr Bohr claimed electrons move in paths around the nucleus. They are very small without much mass. History of the Atom

11. http:// regentsprep.org/Regents/physics/phys05/catomodel/cloud.htm What is the Electron Cloud Model? Model of the atom pictures the electrons moving around the nucleus in a region called an electron cloud. The electron cloud is a cloud of varying density surrounding the nucleus. The varying density shows where an electron is more or less likely to be. Atoms with electrons in higher energy levels have additional electron clouds of different shapes that also show where those electrons are likely to be.

12. What is the Electron Cloud Model? Do you know what these are called? Electron Orbital

13. Orbital Electrons can spin in any direction; scientists cannot tell exactly where an electron is at a given moment or where it is going. They can calculate the probability that an electron will be found in a given space. This is quantum mechanics. The distance from the nucleus that the electron spins is called its energy shell, energy level, or orbital.

14. Electrons are arranged in Energy Levels or shells around the nucleus of an atom. The first shell can hold 2 electrons The second shell can hold 8 electrons The third shell can hold 8 electrons The fourth level can hold 18 electrons The fifth level can hold 32 electrons The sixth level can hold 50 electrons The seventh level can hold 72 electrons Atomic Structure

15. ELECTRONIC CONFIGURATION With electronic configuration elements are represented numerically by the number of electrons in their shells and number of shells. For example; N Nitrogen 7 14 2 in 1 st shell 5 in 2 nd shell configuration = 2, 5 2 + 5 = 7

16. ELECTRONIC CONFIGURATION Write the electronic configuration for the following elements; Ca O ClSi Na 20 40 11 23 8 17 16 35 14 28 B 11 5 a)b)c) d)e)f) 2,8,8,22,8,1 2,8,72,8,42,3 2,6

17. DOT & CROSS DIAGRAMS With Dot & Cross diagrams elements and compounds are represented by Dots or Crosses to show electrons, and circles to show the shells. Nitrogen N XXX X X X X N 7 14

18. Dot and Cross Diagrams Draw the Dot & Cross diagrams for the following elements; OCl 817 16 35 a)b) O X X X X X X X X Cl X X X XX X X X X X X X X X X X X X

19. SUMMARY 1. The Atomic Number of an atom = number of protons in the nucleus. 2. The Atomic Mass of an atom = number of Protons + Neutrons in the nucleus. 3. The number of Protons = Number of Electrons. 4. Electrons orbit the nucleus in shells. 5. Each shell can only carry a set number of electrons.

21. Composition of Matter Elements Compounds Mixtures

22. Composition of Matter Elements: Made of only one type of atom. All atoms are identical. ◦Atom: building block of an element -Molecule: two or more atoms chemically bonded together. Examples: oxygen, nitrogen, iron

23. Compounds: made from atoms of two or more elements that are chemically combined. ◦Examples: water (H2O), table salt(NaCl)

24. Mixtures: made up of two or more substances that are not chemically combined. Easily separated. ◦Examples: soil, ocean water, air Homogeneous mixture: means that mixture is evenly spread out, and no differences can be detected. Ex: water, vinegar Heterogeneous mixture: means that material in mixture is not evenly spread out and differences can be detected. Ex:soil, chocolate chip cookie

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