#24 Why did Mendeleev leave spaces in his periodic table?

1. #24 Why did Mendeleev leave spaces in his periodic table? He could tell from the elements surrounding the “holes” in his table that they must exist.

2. #25 What effect did the discovery of gallium have on the acceptance of Mendeleev’s table? His ability to predict the properties and existence of unknown elements made his table much more believable

3. #26 What pattern is revealed when the elements are arranged in a periodic table in order of increasing atomic number? Many trends are revealed such as electronegativity, atomic and ionic radii,

4. #27 Based on their locations in the periodic table, would you expect carbon and silicon to have similar properties? Yes, they are in the same group

5. #28 Identify each property below as more characteristic of a metal or a non-metal. a. gas at room temp. non-metal, think of oxygen gas

6. #28 Identify each property below as more characteristic of a metal or a non-metal. b. brittle non-metal, think of a piece of lead in your pencil--Carbon

7. #28 Identify each property below as more characteristic of a metal or a non-metal. c. malleable. metal: think of pounding a piece of gold into leaf with a mallet.

8. non-metal: think of how well metal conducts electricity. ie. a wire. #28 Identify each property below as more characteristic of a metal or a non-metal. d. poor conductor of electric current.

9. #28 Identify each property below as more characteristic of a metal or a non-metal. e. shiny. metal: think of a shiny piece of silver or gold.

10. Metalloids have properties that are similar to both metals and non-metals. How a metalloid behaves depends on the conditions. #29 In general, how are metalloids different from metals and nonmetals?

11. #30 Where are the alkali metals, the alkaline earth metals, the halogens, and the noble gases?

12. #31 Which of the following are symbols for representative elements: Na Mg Fe Ni Cl YES YES NO NO YES

13. #32 Which noble gas does not have eight electrons in its highest occupied energy level? Helium; it only has two all others have 8 valence electrons

14. #33 Which of these metals isn’t a transition metal? a. aluminum b. silver c. iron d. zirconium Transition metals are light blue in this table

15. #34 Use figure 6.12 to write the electron configuration of these elements. a. B b. As c. F d. Zn e. Al

16. #35 Write the electron configurations of these elements: a. the noble gas in period 3 b. the metalloid in period 3 c. the alkali metal in period 3 Ar: 1s22s22p63s23p6 Si: 1s22s22p63s23p2 Na: 1s22s22p63s1

17. #36 Which element in each pair has atoms with a larger atomic radius? a. sodium, lithium

18. #36 Which element in each pair has atoms with a larger atomic radius? b. strontium magnesium

19. #36 Which element in each pair has atoms with a larger atomic radius? c. carbon germanium

20. #36 Which element in each pair has atoms with a larger atomic radius? d. selenium oxygen

21. #37Explain the difference between the first and second ionization energy of an element. First ionization energy is the energy required to remove the FIRST electron Second ionization energy is the energy required to remove the SECOND electron. It is always GREATER THAN the first ion- ization energy

22. #38 Which element in each pair has • a greater first ionization energy? • lithium • boron Boron

23. #38 Which element in each pair has • a greater first ionization energy? • magnesium • strontium Magnesium

24. #38 Which element in each pair has • a greater first ionization energy? • cesium • aluminum Aluminum

25. #39 Arrange the following groups of elements in order of increasing ionization energy. Sr Mg Be

26. #39 Arrange the following groups of elements in order of increasing ionization energy. Cs Ba Bi

27. #39 Arrange the following groups of elements in order of increasing ionization energy. Na Al S

28. Atomic Radius as compared to IONIC radius Atoms in elemental form (same # of electrons as protons) Ions

30. 1 1 1 1 1