Periodic Properties of the Elementsauthor: Dr. Robert D. Craig, Ph.D

Periodic Properties of the Elements

• Today we will look at some actually reactions and record observations for the

Further understanding of metallic reactivity

Periodic Properities of the Elements**

Group 17A The Halogens metals Sodium and Potassium

• Pic of halogens

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.

Gases at first the liquids as you go down

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.

begin

• Page 1 of 11• Group VIIA chlorine, bromine, iodine and

flourine

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• Locate these elements on the periodic table (46)

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)

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• Then add 1 mL of methylene chloride to the tube. Cork it, and invert the tube gently to mix the contents

• Do Not Shake!!

(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)

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• 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.

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• 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).

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• Write a chemical equation for the reaction (53)

.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.

Page 1 item 4

• Account for the color changes that are observed (55). Write a chemical equaiton for the reaction (56)

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

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• 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).

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)

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• The instructor will place Al2O3 , CaO, ZnO, Ag2O, HgO into individual dry test tubes.

• Observe split for production of Oxygen

OXIDES OF ELEMENTS

• Which of the tested oxides are most thermally stable? (61)

• Which are the tested oxides are least thermally stable? (62)

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)

OXIDES OF ELEMENTS

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

Part III

• EVIDENCE FOR THE PRESENCE OF ION IN AQUEOUS SOLUTION

• Please observe demo!!!• Electric light circuit to measure conductivity

Familiar with this by now