Chemistry Chapter 6 Study Guide

Actinide and Lanthanide Series

• Actinide series comprises f-block elements from period 7, following actinium.
• Lanthanide series consists of f-block elements from period 6, following lanthanum.

Periodic Table Groups

• Alkali metals (Group 1) are highly reactive, excluding hydrogen, and mainly exist as compounds.
• Alkaline earth metals (Group 2) are also highly reactive.
• Halogens (Group 17) are known for their high reactivity.
• Noble gases (Group 18) are extremely unreactive.
• Representative elements include groups 1, 2, and 13-18, showcasing diverse chemical and physical properties.
• Transition elements span groups 3-12 in the d-block, featuring filled outermost s orbital and partially filled d orbitals.

Definitions and Properties

• Electronegativity rates the tendency of an atom to attract electrons in a bond.
• Ionization energy is the energy needed to remove an electron from a gaseous atom, increasing across a period and decreasing down a group.
• An ion is an atom or bonded group with a positive or negative charge.
• Metal properties include the ability to conduct heat, being hard, shiny, and malleable.
• Nonmetals are generally gaseous or dull, brittle solids, poor conductors of heat and electricity.

Periods and Atomic Structure

• Periods are horizontal rows indicating increasing atomic number and periodic repetition of properties.
• Each period represents a specific energy level, while groups (or families) represent vertical columns with similar chemical properties.
• Atomic and ionic radii decrease from left to right and increase down a group.

Historical Contributions to the Periodic Table

• Newlands proposed the "Law of Octaves" in 1864, noting the repetition of properties every eighth element.
• Meyer and Mendeleev organized elements by increasing atomic mass, creating columns of similar properties while predicting undiscovered elements.
• Mosley established the modern periodic table arrangement based on increasing atomic number through X-ray experiments.

Chemical Stability and Electron Configuration

• According to the octet rule, atoms tend to lose, gain, or share electrons to attain a stable configuration resembling that of noble gases.
• Atoms require eight electrons in their outer level for chemical stability; elements with three or fewer outer electrons typically behave like nonmetals.

Trends in the Periodic Table

• Electronegativity and ionization energies increase across a period and decrease down a group.
• Nonmetallic character enhances with an increasing atomic number in a period.