Relationships in the Periodic Table Laila Jones Vickers March 29, 2023 Section: Chem 4B QR9 Professor Katash
Introduction: The purpose of this experiment is to explore the relationship between the properties of the elements and their positions in the periodic table. Specifically the differences and similarities in the properties of the elements in Group I, II, III, and VII. As well as the trends in basicity and acidity of the oxides of the elements in the third period. The purpose of the periodic table is to be able to referrer to important information about the elements, specifically the atomic weight, periodicity of the chemicals due to their repeating patterns, and physical properties of the elements. The order of the periodic table is arranged by atomic weight and valence electrons The periodic table has changed a lot overtime, the early periodic table allows chemists to notice elements groupings based on similar properties and reactions observed like sodium, lithium, and potassium. A reworking of the way chemists and the world view the periodic table is accredited to Russian chemist Dmitri Mendeleev from his 1869 paper "The Relation of the Properties to the Atomic Weights of the Elements". He had reorganized and then with his new knowledge organized the elements according to their atomic weight, and formatted the table that formed columns and rows that focused on the grouped elements "families". He also noticed a need for transition metals when he knew there needed to be a change after calcium (Ca). Even after that he acknowledged the gaps in the table, an implication that new elements were yet to be discovered. Now the table, a modern version of Mendeleev's table, is organized by increasing atomic number (Z), how many protons are present in an atom, and demonstrating the periodicity of chemical and physical properties. This experiment explores different trends and groups on the periodic table. Part I, explores the reactivity and behavior of group I, II, and III metals by their reactions in water and HCl. Part II, focuses on the halogen properties a part of group VIIA and how the physical state is
affected by molecular weight. Part III, the last part, uses litmus paper to compare the pacific or basic properties of third period hydroxides. This experiment explores and draws conclusions of the trends across the periodic table. Experiment & Results: I. The Behavior of the Metals of Groups I, II, and III A. Sodium + Water / Potassium + Water (Instructor Demo) 1. Procedure: The instructor demonstrated the reaction of Na and K with water. Beginning with 3/4th's of a liter beaker with water and 4 drops of phenolphthalein indicator were added and stirred in. Then a small piece of sodium was dropped into the beaker. This procedure was repeated with potassium. 2. Observations: a) When water and phenolphthalein indicator were mixed it was a clear solution, and the sodium solids with mineral oil were soft with a shiny inside. The reaction of the sodium solids dropped in the phenolphthalein