Atomic Structure and the Periodic Table

1. Atomic Structure and the Periodic Table Students can describe the parts of an atom Students can read the element information on the periodic table Students can describe the reactivity of alkali metals Students can describe how various types of bonding in different categories of materials effects their behavior

2. Atoms • smallest particle of an element that has the properties of the element • made of 3 basic subatomic particles • there are now many more subatomic particles – theoretical physics

3. nucleus • small, dense center of atom • contains almost all the mass of the atom • contains protons and neutrons

4. Atomic Mass Unit (amu) • metric unit to measure the mass of VERY small objects (particles) • a unit to measure the mass of atoms

5. Subatomic Particles

6. Subatomic Particles

7. # of protons • atomic number • whole number on periodic table • number of protons in an atom of an element • does NOT vary in an element – the same in all atoms of an element

8. # of electrons • atoms are neutral • (+) = (-) • # of protons = # of electrons • p = e-

9. atomic mass (weight) • decimal number on the periodic table – it is for all the atoms of the element • number of protons plus the number of neutrons – it’s an average on the table • weighted average of all the isotopes of that element • the mass of one atom is a whole number

10. Isotopes • iso = same • atoms of the same element with different numbers of neutrons • have different atomic masses but the same atomic number • some are stable, some are radioactive (carbon-12 and carbon-14)

12. Free Write • What do you know about: • atoms • the periodic table

13. Periodic Table • How is the periodic table arranged? • arranged by increasing atomic number • rows • called periods • tells number of electron shells • number them down the left side of the periodic table – 1 through 7

15. Periodic Table • columns • called families or groups • elements in same column have similar chemical properties • same number of valence electrons

16. Ion • atom with a charge • atom has gained or lost electrons • gained e- = (-) charge • lost e- = (+) charge • (+) ion = cation • (-) ion = anion

17. Column 1 • alkali metals • want to give away one electron • most reactive metals

18. Alkali metals on the show brainiac

19. Bonding • atoms achieve a stable number of electrons (ionic and covalent) • involves valence (outer) electrons • make compounds and/or solids

21. Metallic Bonding All pure metals have metallic bonding and therefore exist as metallic structures.  Metallic bonding consists of a regular arrangement of positive ion cores of the metals surrounded by a mobile delocalized sea of electrons.

23. Metallic Bonding • Each atom donates its valence electrons to the whole • Atom therefore becomes a cation (here called an ion core) • Donated electrons form an electron cloud surrounding all the ion cores • Electron cloud binds all the ion cores together by coulombic forces

24. Metallic Bonding • Valence electrons are delocalized: • Shared by all atoms in the material • Electrons are free to drift throughout the material • Provides unique properties only found in metals • shiny metallic luster • good electrical and thermal conductivity • many others ...

25. Metallic Bonds:  Mellow dogs with plenty of bones to go around These bonds are best imagined as a room full of puppies who have plenty of bones to go around and are not possessive of any one particular bone.  This allows the electrons to move through the substance with little restriction.  The model is often described as the "kernels of atoms in a sea of electrons."

26. Ionic Bonding(ceramics and polymers)

27. Ionic Bonds: One big greedy thief dog! Ionic bonding can be best imagined as one big greedy dog stealing the other dog's bone.  If the bone represents the electron that is up for grabs, then when the big dog gains an electron he becomes negatively charged and the little dog who lost the electron becomes positively charged.  The two ions (that's where the name ionic comes from) are attracted very strongly to each other as a result of the opposite charges.

29. Sodium lets Chlorine use its valance electron

30. Covalent Bonding(Ceramics)

31. Covalent Bonds: Dogs of equal strength. Covalent bonds can be thought of as two or more dogs with equal attraction to the bones.  Since the dogs (atoms) are identical, then the dogs share the pairs of available bones evenly.  Since one dog does not have more of the bone than the other dog, the charge is evenly distributed among both dogs.  The molecule is not "polar" meaning one side does not have more charge than the other.

32. Polar Covalent Bonds: Unevenly matched but willing to share. These bonds can be thought of as two or more dogs that have different desire for bones.  The bigger dog has more strength to possess a larger portion of the bones.  Sharing still takes place but is an uneven sharing.In the case of the atoms, the electrons spend more time on the end of the molecule near the atom with the greater electronegativity (desire for the electron) making it seem more negative and the other end of the molecule seem more positive.

35. http://www.bbc.co.uk/scotland/education/bitesize/higher/chemistry/energy/bsp1_rev.shtmlhttp://www.bbc.co.uk/scotland/education/bitesize/higher/chemistry/energy/bsp1_rev.shtml • Read the 4 slides and take the quiz at the end • Patterns in the periodic table • http://www.ewart.org.uk/science/structures/str13.htm • Ionic bonding Electron numbers ions and aions • http://www.ewart.org.uk/science/structures/str14.htm • Covalent bonding • http://www.ewart.org.uk/science/structures/str7.htm • Structure of the atom