The Periodic Table

1. The Periodic Table Elements are arranged in groups based on properties

2. The Periodic Table Dmitri Mendeleev arranged the elements according to atomic mass and used the arrangements to predict the properties of missing elements.

3. The Periodic Table • The modern periodic table is arranged in order of increasing atomic number. • The atomic number is the total number of protons in the nucleus. • The electron mostly determines the properties of an element.

4. The Periodic Table • Indium: • ______ protons ______ electrons • 49 49

5. The Periodic Table • GROUPS vertical columns • Old 1A - 8A new 1 - 18

6. Periods - horizontal rows • Magnesium is in the same group as calcium. • Magnesium is in the same period as phosphorus.

7. The three classes of elements are: metals, nonmetals, and metalloids.

8. The Periodic Table • Metals include the majority of the elements. Pt is a metal. Si is a metalloid. Kr is a nonmetal. • Metals are shiny, malleable (hammered into sheets), ductile (drawn into wires), solid at room temperature, and good conductors of electricity.

9. The Periodic Table • Nonmetals are poor conductors of electricity, often gases at room temperature, and brittle if solid. • Metalloids have some properties of metals and nonmetals.

10. Group 1A - alkali metals

11. Group 2A - alkaline earth metals

12. Group 7A - halogens

13. Group 8A - noble gases

14. Groups 1A through 7A - representative elements

15. Group B - transition metals

16. The Periodic Table • Aluminum is a representative element. • Copper is a transition metal. • Na is an _______________________ • Mg is an _______________________ • F is a ________________________ • Ne is a ______________________ • Ag is a ______________________

17. The Periodic Table • Na is an alkali metal • Mg is an alkaline earth metal • F is a halogen • Ne is a noble gas • Ag is a transition metal

18. The Periodic Table • There are 5 electrons in the valence level of an element in Group 5A. • N, P, As, and Sb have the same number of electrons in their valence levels.

19. The Periodic Table • The electron configuration for an element in the halogen group should always end with ns2np5. • The electron configuration of the element chlorine ends in 3s23p5.

20. The Periodic Table • Noble gases (inert gases) have their highest occupied s and p sublevels filled. • Fe contains an electron in a d sublevel.

21. Atomic size • The atomic radius increases from top to bottom in a group in the periodic table. • As you move down a group in the periodic table, atomic size generally increases

22. Atomic size • The atomic radius decreases from left to right across a period in the periodic table. • Lithium has the largest atomic radius in the second period. • As the number of electrons added to the same energy level increases, atomic size generally decreases.

23. Atomic size • List the symbols for sodium, sulfur, and cesium in order of increasing atomic radii _____________________ The largest atom in Group 1A is ______________ • The smallest atom in Group 7A is ______________

24. Atomic size • List the symbols for sodium, sulfur, and cesium in order of increasing atomic radii: S, Na, Cs • The largest atom in Group 1A is Fr. • The smallest atom in Group 7A is F.

25. Ions & Ionization • Ions form when electrons enter or leave atoms.

26. Ions & Ionization • The charge of a cation is positive. Cations are smaller than the original atom. • An anion has a negative charge. Anions are larger than the original atom.

27. Ions & Ionization • Removing one electron from an atom results in the formation of an ion with a 1+ charge.

28. Ions & Ionization • Ionization energy - energy required to move an electron out of an atom • Ionization energy decreases from top to bottom and increases from left to right on the periodic table.

29. Ions & Ionization • Among Na, K, and Cs, which element has the lowest ionization energy? • Which is larger, K or K+? • Which is smaller, Li, Li+, F, or F- ?

30. Ions & Ionization • Among Na, K, and Cs, which element has the lowest ionization energy? Cs • Which is larger, K or K+? K • Which is smaller, Li, Li+, F, or F- ? Li+

31. Electronegativity • Electronegativity is the ability of an atom in a compound to attract electrons

32. Electronegativity • Electronegativity values tend to decrease from top to bottom and increase from left to right.

33. Electronegativity • Which element in each pair has a higher electronegativity value? • Mg, Ne • Cl, F • C, N • As, Ca

34. Electronegativity • Which element in each pair has a higher electronegativity value? • Mg, Ne Mg • Cl, F F • C, N N • As, C As

35. Electronegativity • Cs has one of the lowest electronegativity values.

36. Electronegativity • Valence (outer) electrons may be transferred from one atom to another.

37. Group Valence Resulting electrons charge • 1A Lose 1 1+ • 2A Lose 2 2+ • 3A Lose 3 3+

38. 5A Gain3 3-6A Gain 2 2-7A Gain 1 1-

39. Electronegativity What charge would Na likely have in a compound? _______ What charge would Mg likely have in a compound? _______ What charge would Al likely have in a compound? _______

40. Electronegativity • What charge would Na likely have in a compound? 1+ • What charge would Mg likely have in a compound? 2+ • What charge would Al likely have in a compound? 3+

41. Electronegativity • What charge would O likely have in a compound? _______ • What charge would F likely have in a compound? _______

42. Electronegativity • What charge would O likely have in a compound? 2- • What charge would F likely have in a compound? 1-