The atomic radius is the distance from the atomic nucleus to the outermost stable electron orbital in an atom that is at equilibrium. The atomic radius tends to decrease as one progresses across a period from left to right because the effective nuclear charge increases, thereby attracting the orbiting electrons and lessening the radius. The atomic radius usually increases while going down a group due to the addition of a new energy level (shell). However, diagonally, the number of electrons has a larger effect than the sizeable radiu

1. Periodic Properties of the Elements
author: Dr. Robert D. Craig, Ph.D

2. Periodic Properties of the Elements
• Today we will look at some actually reactions
and record observations for the

3. Further understanding of metallic
reactivity

4. Periodic Properities of the Elements**
Group 17A The Halogens metals Sodium and
Potassium
• Pic of halogens

5. Group 17 is a family of elements
known as the halogens. The word
"halogen" means "salt-former."
halogens will typically take an electron from a metal or even a
weaker nonmetal to complete the desired octet. The ions
formed by this transfer of electrons to the nonmetal are
negatively charged because they have more electrons than
protons. They are called anions.

6. Gases at first the liquids as you go
down

7. Group 17
• Fluorine is the element with the most
electronegativity on the entire periodic table.
Electronegativity is the measure of how
strongly an element will attract electrons
away from other atoms. Its very high
electronegativity makes fluorine the most
reactive element.

8. begin
• Page 1 of 11
• Group VIIA chlorine, bromine, iodine and
flourine

9. .
• Locate these elements on the periodic table
(46)

10. Can use website .
• 2. Add 1 mL of chlorine water (chlorine
dissolved in water) to a 13 x 100 mm test tube
• Containing 3 mL of 0.1 M potassium bromide
(KBr)

11. .
• Then add 1 mL of methylene chloride to the
tube. Cork it, and invert the tube gently to
mix the contents
• Do Not Shake!!

12. (48-50) page 1
• Record the observations – note the color of
the botton layer (48) . Account for the color
changes that are observed (49)
Write a chemical equation for the reation (50)

13. .
• 3. Add 1 mL of chlorine water to a 13 x 100
mm test tube containing 3 mL of 0.1 M
potassium iodide. (kI). Then add 1 mL of
methylene chloride to the tube.

14. .
• Cork it, and invert the tube gently to mix the
contents.
• Record the obersevations- note the color of
the bottom layer (51). Account for the color
changes that are observed (52).

15. .
• Write a chemical equation for the reaction
(53)

16. .same for bromine
• 4. Add 1 mL of bromine water to a 13 x 100
mm test tube containing 3 mL of 0.1 M
potsassium iodide (KI). Then add 1 mL of
methylene chloride to the tube.

17. Page 1 item 4
• Account for the color changes that are
observed (55). Write a chemical equaiton for
the reaction (56)

18. .
• 5. What can be said about the relative
chemical reactivities of chlorine, bromine, and
iodine especially with respect fo tone another
(57)?

19. .
• I. Restudy the results in section A through H
and write a paragraph about the chemical and
physical properties of the elements.
Comment on the way in which the properties
vary the position of the element in table (58).

20. Page 2 OXIDES OF ELEMENTS
• You will see demonstrations
• Please have googles
• You will be asked to record the observations
item (59) and write the chemical reactions
that occur (60)

21. .
• The instructor will place Al2O3 , CaO, ZnO,
Ag2O, HgO into individual dry test tubes.
• Observe split for production of Oxygen

22. OXIDES OF ELEMENTS
• Which of the tested oxides are most thermally
stable? (61)
• Which are the tested oxides are least
thermally stable? (62)

23. OXIDES OF ELEMENTS
• Students do this part
• Drop a small piece of calcium oxide into a test
tube containing 5 ml of water. Test the
resulting solution with litmus paper.
• Write an equation for the reaction (64)

24. OXIDES OF ELEMENTS
• Compare these results with those of
experiments with phosphorus, Par I- F (1) and
sulfur Part I- G (1) (65)

25. Part III
• EVIDENCE FOR THE PRESENCE OF ION IN
AQUEOUS SOLUTION
• Please observe demo!!!
• Electric light circuit to measure conductivity

26. Familiar with this by now