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Background
Background
Background During the 19th century, chemists were noticing that there were various trends and patterns associated with the elements. Attempts were made to rationalize these patterns by arranging the elements in groups, forming a periodic table of the elements.
Background During the 19th century, chemists were noticing that there were various trends and patterns associated with the elements. Attempts were made to rationalize these patterns by arranging the elements in groups, forming a periodic table of the elements.
Johann Döbereiner grouped atoms in threes, forming triads in which all of the substituents had similar chemical properties, and the atomic mass of the middle element was approximately the average of the other two atomic masses. John Newlands devised a law of octaves, with an eight-step period similar to the musical scale. However, it was Dmitri Mendeleev who made a periodic table similar to the one we use today. The genius of Mendeleev’s work was that it included dashes as placeholders for undiscovered elements. Furthermore, because of the periodic trends he could observe throughout his table, he was able to predict the properties of the undiscovered elements. For example, Mendeleev had a dash below aluminum for a new element that he predicted would be a metal with an atomic mass of approximately 68 u, a density of 5.9 g/cm3, and a low melting point. Gallium was discovered fewer than five years after these predictions were made and was found to be a metal with an atomic mass of 69.723 u, a density of 5.904 g/cm3, and a melting point of 29.7 °C.
Johann Döbereiner grouped atoms in threes, forming triads in which all of the substituents had similar chemical properties, and the atomic mass of the middle element was approximately the average of the other two atomic masses. John Newlands devised a law of octaves, with an eight-step period similar to the musical scale. However, it was Dmitri Mendeleev who made a periodic table similar to the one we use today. The genius of Mendeleev’s work was that it included dashes as placeholders for undiscovered elements. Furthermore, because of the periodic trends he could observe throughout his table, he was able to predict the properties of the undiscovered elements. For example, Mendeleev had a dash below aluminum for a new element that he predicted would be a metal with an atomic mass of approximately 68 u, a density of 5.9 g/cm3, and a low melting point. Gallium was discovered fewer than five years after these predictions were made and was found to be a metal with an atomic mass of 69.723 u, a density of 5.904 g/cm3, and a melting point of 29.7 °C.
Introduction How did the periodic table get its shape? Looking for patterns and developing models can help us to make sense of the world. In this activity you will make your own “periodic table of the animals” by applying scientific thinking and looking for patterns. Afterward you will play “periodic table solitaire” by arranging cards with real elemental data.
Introduction How did the periodic table get its shape? Looking for patterns and developing models can help us to make sense of the world. In this activity you will make your own “periodic table of the animals” by applying scientific thinking and looking for patterns. Afterward you will play “periodic table solitaire” by arranging cards with real elemental data.
Introduction
Introduction
Purpose: The purpose of this lab is to learn how to observe various trends and patterns associated with the elements.
Procedure: Use the colored animals to create a periodic table of elements by applying scientific thinking and looking for patterns followed by applying this knowledge to cards with real elemental data.
Prelab Assignment
Prelab Assignment
Prelab Assignment: Answer the following questions in complete sentences and thoughts, using the information from the lab to support your answers. For math questions, show all of your work including significant figures and units in order to receive FULL credit.
Directions: Watch the Flinn lab demo video and read the background information on the Periodic table and answer the questions below.
What major contribution did Johann Dobereiner make to the development of the Periodic Table?
What major contribution did John Newland make to the development of the Periodic Table?
What major contribution did Dmitri Mendeleev make to the development of the Periodic Table?
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