Periodic Table Chapter 5 Flashcards

Dmitri Mendeleev and the Periodic Table

• Mendeleev arranged elements in rows by increasing atomic mass, grouping similar properties in columns.
• Developed his table by playing a game of solitaire, leading to an organized method for categorizing elements.

Predictions and Verification

• Mendeleev predicted properties of undiscovered elements based on existing elements near blank spaces in his table.
• The accuracy of his predictions and close matches with actual discovered elements confirmed the utility of his periodic table.

Missing Element

• Mendeleev referred to the unknown element below Aluminum as eka-aluminum, later discovered as gallium in 1875.

Gallium

• Gallium is utilized in traffic signals and small light-emitting diodes (LEDs).

Structure of the Modern Periodic Table

• The modern periodic table is organized by increasing atomic number (number of protons) rather than mass.
• Rows are termed periods, with a total of 7 periods and columns referred to as groups.

Periodic Law

• Periodic law states that physical and chemical properties of elements recur in a predictable manner with increasing atomic number.

Atomic Mass

• Atomic mass is influenced by the natural distribution of an element's isotopes and their individual masses.
• The atomic mass unit is defined as one twelfth the mass of a carbon-12 atom.

Element Information

• Each element is described by four pieces of information: atomic mass, atomic number, element symbol, and element name.

Classification of Elements

• Elements are categorized as metals, nonmetals, and metalloids.
• Transition metals span groups 3 through 12, acting as a bridge between left and right elements.

Properties of Metals and Nonmetals

• Metals: Good conductors of electricity and heat, malleable, ductile, and high boiling points.
• Nonmetals: Brittle, poor conductors, low boiling points, and the most reactive nonmetal is fluorine.

Metalloids

• Metalloids possess properties between metals and nonmetals.

Trends Across the Periodic Table

• As one moves left to right across a period, elements trend from metallic properties to nonmetallic properties.
• Elements in the same group share similar properties due to identical valence electron counts.

Valence Electrons

• Valence electrons are located in the highest occupied energy level of an atom and determine chemical reactivity.
• Hydrogen, having one valence electron, is placed with alkali metals in Group 1A.

Alkali and Alkaline Earth Metals

• Group 1A elements are called alkali metals; their reactivity increases down the group.
• Group 2A elements are known as alkaline earth metals and contain two valence electrons.

Test your knowledge on Chapter 5 of the Periodic Table with these flashcards. Explore how Mendeleev organized elements by their properties and learn the significance of the periodic arrangement. Perfect for students looking to reinforce their understanding of chemistry.