Understanding Atomic Structure and the Periodic Table

2. Protons are in the nucleus (center) of the atom • Have a positive charge • Neutrons are in the nucleus (center) of the atom • Are neutral; have no charge • Electrons move in energy levels outside of the nucleus • Have a negative charge • Nucleus contains both protons and neutrons and most of the atoms mass • Have a positive charge http://jchemed.chem.wisc.edu/JCESoft/CCA/pirelli/pages/cca3NI3.html

3. The columns are called groups or families. Groups have similar physical and chemical properties and the same number of valence electrons

4. Name the groups boxed in yellow, orange, green and blue.

5. Name the groups boxed in yellow, orange, green and blue. Alkali metals, Alkaline Earth metals, Halogens, and Noble or Inert Gases.

6. The rows are called periods. The period number matches the principle energy level of the element. This will be the principle energy level of the valence electrons.

7. What is the principle energy level of Nickel, Ni?

8. What is the principle energy level of Nickel, Ni? 4—it is in the row numbered 4

9. Chemistry SOL Review—Atomic Structure Using the SOL Periodic Table Click on the link to get the SOL periodic table Keep this Adobe file open as you work on the review Let’s use the periodic table to answer some questions about Silicon

10. Chemistry SOL Review—Atomic Structure Using the SOL Periodic Table Let’s use the periodic table to answer some questions about Silicon. How many protons does Silicon have?

11. Chemistry SOL Review—Atomic Structure Using the SOL Periodic Table Let’s use the periodic table to answer some questions about Silicon. How many protons does Silicon have? 14 protons = atomic number. How many electrons does neutral Silicon have?

12. Chemistry SOL Review—Atomic Structure Using the SOL Periodic Table Let’s use the periodic table to answer some questions about Silicon. How many protons does Silicon have? 14 protons = atomic number. How many electrons does neutral Silicon have? 14 electrons (# electrons = # protons in neutral atoms) How many neutrons does Silicon-30 have?

13. Chemistry SOL Review—Atomic Structure Using the SOL Periodic Table Let’s use the periodic table to answer some questions about Silicon. How many protons does Silicon have? 14 protons = atomic number. How many electrons does neutral Silicon have? 14 electrons (# electrons = # protons in neutral atoms) How many neutrons does Silicon-30 have? 16 neutrons. Silicon-30 is an isotope of Silicon. It has a mass number of 30. The mass number is protons + neutrons.

14. Chemistry SOL Review—Atomic Structure Using the SOL Periodic Table Let’s use the periodic table to answer some questions about Silicon. How many protons does Silicon have? 14 protons = atomic number. How many electrons does neutral Silicon have? 14 electrons (# electrons = # protons in neutral atoms) How many neutrons does Silicon-30 have? 16 neutrons. Silicon-30 is an isotope of Silicon. It has a mass number of 30. The mass number is protons + neutrons. What is the molar mass of Silicon?

15. Chemistry SOL Review—Atomic Structure Using the SOL Periodic Table Let’s use the periodic table to answer some questions about Silicon. How many protons does Silicon have? 14 protons = atomic number. How many electrons does neutral Silicon have? 14 electrons (# electrons = # protons in neutral atoms) How many neutrons does Silicon-30 have? 30 neutrons. Silicon-30 is an isotope of Silicon. It has a mass number of 30. The mass number is protons + neutrons. What is the molar mass of Silicon? 28.0855 grams/mole (this is the same as the atomic mass on the periodic table)

16. Chemistry SOL Review—Atomic Structure Using the SOL Periodic Table Let’s use the periodic table to answer some questions about Silicon. How many protons does Silicon have? 14 protons = atomic number. How many electrons does neutral Silicon have? 14 electrons (# electrons = # protons in neutral atoms) How many neutrons does Silicon-30 have? 30 neutrons. Silicon-30 is an isotope of Silicon. It has a mass number of 30. The mass number is protons + neutrons. What is the molar mass of Silicon? 28.0855 grams/mole (this is the same as the atomic mass on the periodic table) How many valence electrons does Silicon have?

17. Chemistry SOL Review—Atomic Structure Using the SOL Periodic Table Let’s use the periodic table to answer some questions about Silicon. How many protons does Silicon have? 14 protons = atomic number. How many electrons does neutral Silicon have? 14 electrons (# electrons = # protons in neutral atoms) How many neutrons does Silicon-30 have? 30 neutrons. Silicon-30 is an isotope of Silicon. It has a mass number of 30. The mass number is protons + neutrons. What is the molar mass of Silicon? 28.0855 grams/mole (this is the same as the atomic mass on the periodic table) How many valence electrons does Silicon have? 4 valence electrons. Look for electrons in the highest principle energy level.

18. Chemistry SOL Review—Atomic Structure An s orbital holds 2 electrons w/ opposite spins

19. Chemistry SOL Review—Atomic Structure Each p orbital holds 2e- with opposite spins

20. Chemistry SOL Review—Atomic Structure Each d orbital holds 2e- with opposite spins

21. Chemistry SOL Review—Atomic Structure The orbitals and the periodic table The s suborbital fills

22. Chemistry SOL Review—Atomic Structure The orbitals and the periodic table The p suborbitals fill

23. Chemistry SOL Review—Atomic Structure The orbitals and the periodic table The d suborbitals fill

24. Chemistry SOL Review—Atomic Structure Valence electron configuration and the periodic table All group 13 elements have the valance electron configuration ns2np1.and 3 valence electrons

25. Chemistry SOL Review—Atomic Structure Valence electron configuration and the periodic table All group 15 elements have the valance electron configuration ns2np3.and 5 valance electrons.

26. Chemistry SOL Review—Atomic Structure Valence electron configuration and the periodic table What is the valence configuration of the halogens?

27. Chemistry SOL Review—Atomic Structure Valence electron configuration and the periodic table What is the valence configuration of the halogens? ns2np5.

28. Chemistry SOL Review—Atomic Structure Periodic Trends in Atomic Radius, Ionization Energy, and Electronegativity. Atomic Radius: the radius of an atom in picometers First Ionization Energy: The energy needed to remove the first valence electron from a gaseous atom. Electronegativity: The tendency of an atom to attract electrons to itself when chemically combined with another element.

29. Chemistry SOL Review—Atomic Structure Periodic Trends in Atomic Radius, Ionization Energy, and Electronegativity. Atomic Radius: the radius of an atom in picometers • 2 13 14 15 16 17 18

30. Chemistry SOL Review—Atomic Structure Periodic Trends in Atomic Radius, Ionization Energy, and Electronegativity. First Ionization Energy: The energy needed to remove the first valence electron from a gaseous atom. Ionization energy increases as you move to higher number groups. Group 18 has the highest 1st ionization energy. Ionization energy decreases as you move down the periodic table.

31. Chemistry SOL Review—Atomic Structure Periodic Trends in Atomic Radius, Ionization Energy, and Electronegativity. First Ionization Energy: The energy needed to remove the first valence electron from a gaseous atom.

32. Chemistry SOL Review—Atomic Structure Periodic Trends in Atomic Radius, Ionization Energy, and Electronegativity. Electronegativity: The tendency of an atom to attract electrons to itself when chemically combined with another element. The halogen group has the highest electronegativity of the families. The first period has the highest electronegativity. Noble gases do not have electronegativity as the valence shell is already full.

34. Anions, Cations, and Electron Configuration Cations form by losing valance electrons to take on a noble gas configuration (ns2np6)

35. Chemistry SOL Review—Atomic Structure Anions, Cations, and Electron Configuration Cations form by losing valance electrons to take on a noble gas configuration (ns2np6) So Li loses the 2s1 electron to form Li+1. Mg loses both 3s2 electrons to form Mg+2 Al loses three electrons from 3s23p1 to form Al+3 http://jchemed.chem.wisc.edu/JCESoft/CCA/pirelli/pages/cca2ferrofluid.html

36. Chemistry SOL Review—Atomic Structure Anions, Cations, and Electron Configuration Anions form by gaining valance electrons to take on a noble gas configuration (ns2np6) So F becomes F1- by gaining a 2p electron to have the new valance configuration 2s22p6. S becomes S2- by gaining two 2p electrons to have the new valance configuration 3s23p6. N becomes N3- by gaining three 2p electrons to have the new valance configuration 2s22p6.

37. Chemistry SOL Review—Atomic Structure 12 6 13 6 14 6 C C C Isotopes: elements with the same number of protons, but a different number of neutrons. Carbon-14 has ___ protons and ___ neutrons

38. Chemistry SOL Review—Atomic Structure 12 6 13 6 14 6 C C C Isotopes: elements with the same number of protons, but a different number of neutrons. Carbon-14 has 6 protons and 8 neutrons

39. Chemistry SOL Review—Atomic Structure 12 6 13 6 14 6 C C C Isotopes: elements with the same mass, the same number of protons, but a different number of neutrons. You figure out the average atomic mass of a compound by using a weighted average of the mass number for each isotope. Example: a sample contains 10% C-13, 60% C-12 and 40% C-14. The average atomic mass is (0.10 x 13) + (0.60 x 12) + (0.30 x 14) = 12.7

40. Radioactivity • Radioactivity: Spontaneous changes in a nucleus accompanied by the emission of energy from the nucleus as a radiation. • Radioactive Half-Life: A period of time in which half the nuclei of a species of radioactive substance would decay.

41. Alpha radiation Alpha radiation is the least penetrating. It can be stopped - or absorbed - by just a sheet of paper. • Beta radiation Beta radiation can penetrate air and paper. It can be stopped by a thin sheet of aluminum. • Gamma radiation Gamma radiation is the most penetrating. Even small levels can penetrate air, paper or thin metal. Higher levels can only be stopped by many centimeters of lead or many meters of concrete.

42. Chemistry SOL Review—Atomic Structure Development of the Atomic Model • Thompson Model • Rutherford Gold Foil Experiment and Model • Bohr Model • Quantum-Mechanical Model The problems of language here are really serious. We wish to speak in some way about the structure of the atoms. But we cannot speak about atoms in ordinary language. Heisenberg

43. Chemistry SOL Review—Atomic Structure Thompson Model • The atom is a positively charged diffuse mass with negatively charged electrons stuck in it. From Mark Rosengarten’s New York Regent’s Powerpoint

44. Chemistry SOL Review—Atomic Structure Rutherford Model • The atom is made of a small, dense, positively charged nucleus with electrons at a distance, the vast majority of the volume of the atom is empty space. Alpha particles shot at a thin sheet of gold foil: most go through (empty space). Some deflect or bounce off (small + charged nucleus). From Mark Rosengarten’s New York Regent’s Powerpoint

45. Chemistry SOL Review—Atomic Structure Bohr Model • Electrons orbit around the nucleus in energy levels (shells). Atomic bright-line spectra was the clue. From Mark Rosengarten’s New York Regent’s Powerpoint

46. Chemistry SOL Review—Atomic Structure Quantum-Mechanical Model • Electron energy levels are wave functions. • Electrons are found in orbitals, regions of space where an electron is most likely to be found. • You can’t know both where the electron is and where it is going at the same time. • Electrons buzz around the nucleus like gnats buzzing around your head. From Mark Rosengarten’s New York Regent’s Powerpoint