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🧶Inorganic Chemistry I

1.3 Periodic Table and Elemental Properties

3 min readLast Updated on August 9, 2024

The periodic table organizes elements based on atomic structure and properties. It's divided into blocks, periods, and groups, each reflecting specific electron configurations and trends. Understanding these patterns helps predict chemical behavior and reactivity.

Elements are classified into main groups, transition metals, and inner transition series. This organization reveals similarities in properties, valence electrons, and chemical reactions. Recognizing these groupings is key to grasping elemental trends and periodic law.

Periodic Table Organization

Structure and Blocks of the Periodic Table

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  • Periods run horizontally across the periodic table, representing increasing atomic number and electron shells
  • Groups form vertical columns, exhibiting similar chemical properties due to shared electron configurations
  • s-block elements occupy the first two groups, characterized by their outermost electrons in s orbitals
  • p-block elements comprise groups 13-18, featuring electrons in p orbitals as their highest energy level
  • d-block elements, known as transition metals, fill the central portion of the table with electrons in d orbitals
  • f-block elements, consisting of lanthanides and actinides, appear as two separate rows below the main table
  • Atomic radius generally decreases across periods and increases down groups
  • Ionization energy tends to increase across periods and decrease down groups
  • Electronegativity typically increases across periods and decreases down groups
  • Metallic character decreases across periods and increases down groups
  • Electron affinity generally increases across periods and decreases down groups
  • Shielding effect influences these trends by reducing the effective nuclear charge experienced by outer electrons

Element Classifications

Main Group Elements and Noble Gases

  • Main group elements encompass s-block and p-block elements, excluding noble gases
  • Alkali metals (Group 1) react vigorously with water, forming strong bases (sodium, potassium)
  • Alkaline earth metals (Group 2) form +2 ions and react with water to produce hydrogen gas (magnesium, calcium)
  • Halogens (Group 17) exist as diatomic molecules and are highly reactive non-metals (chlorine, bromine)
  • Noble gases (Group 18) exhibit extreme stability due to their full outer electron shells (helium, neon)
  • Chalcogens (Group 16) include important elements for biological processes (oxygen, sulfur)

Transition Metals, Lanthanides, and Actinides

  • Transition metals occupy the d-block, characterized by partially filled d orbitals
  • Transition metals often form colored compounds and exhibit variable oxidation states (copper, iron)
  • Many transition metals serve as catalysts in chemical reactions (platinum, palladium)
  • Lanthanides, part of the f-block, share similar chemical properties and are used in various technologies (neodymium in magnets)
  • Actinides, also in the f-block, include radioactive elements used in nuclear energy and weapons (uranium, plutonium)
  • Both lanthanides and actinides exhibit a gradual decrease in atomic radius across their respective series (lanthanide contraction)

Metalloids and Their Unique Properties

  • Metalloids possess properties intermediate between metals and non-metals
  • Located along the stair-step line on the periodic table, separating metals from non-metals
  • Metalloids can form alloys with metals and covalent bonds with non-metals
  • Semiconducting properties make metalloids crucial in electronics industry (silicon, germanium)
  • Boron, a metalloid, forms complex hydrides and is used in neutron-absorbing materials
  • Arsenic, another metalloid, finds applications in wood preservatives and electronic components

Key Terms to Review (39)

Actinides: Actinides are a series of 15 chemical elements in the periodic table, ranging from actinium (Ac, atomic number 89) to lawrencium (Lr, atomic number 103). They are known for being heavy, radioactive metals that display similar properties and are often found in the bottom row of the f-block in the periodic table, indicating their connection to elemental properties like oxidation states and electron configurations.
Alkali metals: Alkali metals are the elements found in Group 1 of the periodic table, characterized by their highly reactive nature, especially with water. They include lithium, sodium, potassium, rubidium, cesium, and francium, and display a trend of increasing reactivity and decreasing ionization energy as you move down the group. Their properties significantly influence both industrial applications and biological systems.
Alkaline Earth Metals: Alkaline earth metals are the six elements in Group 2 of the periodic table, consisting of beryllium, magnesium, calcium, strontium, barium, and radium. These metals are characterized by their shiny appearance, relatively low density, and tendency to form alkaline hydroxides when reacting with water. Their unique properties make them important for various industrial and biological applications.
Alloys: Alloys are materials made by combining two or more elements, where at least one of the elements is a metal. These combinations can result in enhanced properties such as strength, ductility, corrosion resistance, and electrical conductivity. The study of alloys connects deeply to the periodic table, as understanding elemental properties helps predict how different metals will interact when mixed.
Atomic Radius: Atomic radius is defined as the distance from the nucleus of an atom to the outermost shell of electrons. This measurement can vary depending on the type of bond formed and is influenced by factors such as atomic number and electron shielding. Understanding atomic radius helps in predicting bonding behavior and reactivity, which connects directly to the structures and properties of various compounds, especially in p-block and alkali or alkaline earth metal contexts.
Atomic structure: Atomic structure refers to the arrangement of subatomic particles—protons, neutrons, and electrons—within an atom. This arrangement determines the atom's properties, behavior in chemical reactions, and its place in the periodic table. Understanding atomic structure is essential for grasping elemental properties and how different elements interact with one another.
Blocks: In the context of the periodic table, 'blocks' refer to the distinct sections that categorize elements based on their electron configurations and the types of atomic orbitals that are being filled. Each block corresponds to a specific set of elements that share similar properties and reactivity, helping to organize the periodic table into groups such as s-block, p-block, d-block, and f-block. This categorization highlights the relationships between elements and provides insights into their chemical behavior.
Catalysts: Catalysts are substances that increase the rate of a chemical reaction without being consumed in the process. They work by lowering the activation energy required for a reaction to occur, allowing reactants to convert into products more efficiently. Understanding catalysts is crucial in various fields, as they can significantly influence reaction pathways and efficiencies, particularly in energy-related applications and material synthesis.
Chalcogens: Chalcogens refer to the group of elements in Group 16 of the periodic table, which includes oxygen, sulfur, selenium, tellurium, and polonium. These elements are known for their diverse chemical properties and are essential in various biological and industrial processes. Chalcogens play a crucial role in forming compounds with metals and non-metals, impacting both the environment and technology.
Chemical Behavior: Chemical behavior refers to how elements interact with one another during chemical reactions, including the types of bonds they form and their reactivity patterns. This behavior is influenced by the properties of the elements, such as their electron configurations, electronegativity, and ionization energies, which are systematically organized in the periodic table. Understanding chemical behavior helps predict how different elements will react, allowing chemists to anticipate products and develop new compounds.
Colored compounds: Colored compounds are chemical substances that exhibit a distinct color due to the presence of specific electronic transitions, typically involving d-electrons in transition metals. The interaction of light with these compounds results in the absorption of certain wavelengths and the transmission or reflection of others, which gives rise to their characteristic colors. These colors are closely related to the electronic structure of the compound and can provide insights into their chemical properties and behaviors.
Covalent bonds: Covalent bonds are a type of chemical bond that involves the sharing of electron pairs between atoms. This bond is formed when two nonmetal atoms come together and share their valence electrons, resulting in a stable arrangement that lowers the overall energy of the system. Covalent bonds are critical in forming molecules and influence the properties of the substances they create, as well as how these substances interact with each other.
D-block elements: D-block elements are the transition metals found in groups 3 to 12 of the periodic table, characterized by the filling of d orbitals. These elements exhibit unique properties such as variable oxidation states, complex ion formation, and catalytic activity due to their ability to lose different numbers of electrons from their d orbitals.
Diatomic Molecules: Diatomic molecules are molecules composed of two atoms, which can be either of the same element or different elements. These molecules play a significant role in chemistry, especially in understanding elemental properties and behavior, as many of the most common gases we encounter, like oxygen and nitrogen, exist as diatomic species in nature.
Electron Affinity: Electron affinity is the amount of energy released when an atom in the gas phase accepts an electron to form a negative ion. This process is a key factor in determining how atoms interact during the formation of ionic and covalent bonds, and it helps explain various properties and trends observed in groups of the periodic table, particularly in relation to how easily elements can gain electrons.
Electron configurations: Electron configurations describe the arrangement of electrons in an atom's orbitals, indicating how electrons are distributed among the various energy levels and sublevels. This arrangement directly influences an element's chemical properties and behavior, as it determines how an atom interacts with others during chemical reactions. Understanding electron configurations helps to explain trends in elemental properties and variations in atomic and ionic sizes.
Electronegativity: Electronegativity is the tendency of an atom to attract electrons in a chemical bond, reflecting its ability to pull shared electrons toward itself. This property is crucial in understanding bond types, molecular polarity, and the reactivity of different elements. Electronegativity values help predict how atoms will interact during bonding, influencing the properties of compounds formed from elements across various groups of the periodic table.
F-block elements: f-block elements are a group of 14 chemical elements that fill the f-orbitals, located at the bottom of the periodic table. This group includes the lanthanides and actinides, known for their unique properties such as variable oxidation states and magnetic behavior. These elements play essential roles in various applications, from technological advancements to nuclear energy.
Groups: In the context of the periodic table, groups refer to the vertical columns that categorize elements with similar chemical properties and behaviors. Each group contains elements that share the same number of valence electrons, which greatly influences their reactivity and bonding characteristics. This organization helps predict how elements will interact with one another based on their electronic configuration.
Halogens: Halogens are a group of highly reactive nonmetals found in Group 17 of the periodic table, consisting of elements like fluorine, chlorine, bromine, iodine, and astatine. These elements are known for their tendency to form salts when combined with metals, and they play vital roles in various chemical reactions and industrial applications.
Inner transition series: The inner transition series consists of two rows of elements located at the bottom of the periodic table, specifically the lanthanides and actinides. These elements are characterized by the filling of f-orbitals, which leads to unique electronic configurations and a variety of oxidation states, influencing their chemical properties. The inner transition series plays a crucial role in understanding the broader categories of elements and their behaviors within the periodic table.
Ionization Energy: Ionization energy is the amount of energy required to remove an electron from an atom or ion in its gaseous state. This concept is vital for understanding the reactivity of elements, as it influences how easily an element can form ions, which in turn affects bonding and the structures of compounds formed by these elements.
Lanthanides: Lanthanides are a series of 15 chemical elements in the periodic table, ranging from lanthanum (La) to lutetium (Lu), which are known for their similar properties and placement in the f-block. These elements are characterized by their partially filled 4f orbitals, leading to unique magnetic and optical properties. Their significance extends beyond chemistry, impacting various technologies including electronics, optics, and materials science.
Main groups: Main groups refer to the columns of the periodic table that include the s- and p-block elements, which are essential for understanding elemental properties and chemical behavior. These groups encompass a variety of elements, including metals, nonmetals, and metalloids, each with distinct characteristics that influence their interactions and compounds formed with other elements.
Metallic Character: Metallic character refers to the set of properties that are typical of metals, such as high electrical and thermal conductivity, malleability, ductility, and the tendency to lose electrons in chemical reactions. This character decreases across a period from left to right on the periodic table and increases down a group, influencing how elements behave in various chemical contexts and helping to categorize them as metals, nonmetals, or metalloids.
Metalloids: Metalloids are elements that have properties intermediate between metals and nonmetals. These elements typically exhibit a mix of metallic and nonmetallic characteristics, making them versatile in various chemical and physical applications.
Noble gases: Noble gases are a group of elements found in Group 18 of the periodic table, characterized by their full valence electron shells, which makes them highly stable and largely unreactive. This unique electron configuration contributes to their distinctive properties, including low reactivity, odorlessness, and colorlessness, and they are often used in applications requiring inert environments or specific lighting technologies.
P-block elements: P-block elements are a group of elements located in the p-block of the periodic table, which includes groups 13 to 18. These elements are characterized by their diverse properties, varying from metals to nonmetals and metalloids, and play essential roles in various chemical reactions and compounds due to their ability to form covalent bonds.
Periodic Law: Periodic Law states that the properties of elements are a periodic function of their atomic numbers. This means that when elements are arranged by increasing atomic number, similar properties occur at regular intervals. This concept is foundational in understanding the organization of the periodic table and the relationships between elemental properties, which reveal patterns in reactivity, electronegativity, and other characteristics.
Periodic Table: The periodic table is a systematic arrangement of elements, organized by increasing atomic number and grouped by similar chemical properties. This table is essential for understanding the relationships between elements, predicting their behaviors, and exploring trends in elemental properties such as electronegativity, atomic radius, and ionization energy.
Periods: In the context of the periodic table, periods are the horizontal rows that organize elements according to their increasing atomic numbers. Each period signifies the filling of a particular electron shell, which has a profound impact on the chemical properties and behaviors of the elements within that row, as well as how they interact with one another.
Properties: Properties refer to the characteristics or traits of elements that can be observed and measured, influencing their behavior and interactions. These properties are fundamental in understanding how elements fit within the periodic table and how they relate to one another in terms of reactivity, bonding, and structure.
Reactivity: Reactivity refers to the tendency of a substance to undergo chemical reactions, either by itself or with other materials. This characteristic is influenced by factors such as atomic structure, bond formation, and energy levels, which determine how readily an element or compound will interact with others. Understanding reactivity is crucial for predicting how substances will behave in various chemical environments, including their interactions within coordination compounds and organometallic complexes.
S-block elements: S-block elements are a group of chemical elements found in the first two columns of the periodic table, specifically groups 1 and 2, which include the alkali metals and alkaline earth metals. These elements have their outermost electrons in the s subshell, leading to distinct properties and trends such as low ionization energies and high reactivity, especially in water. Understanding s-block elements helps explain key concepts like atomic structure, periodic trends, and elemental properties.
Semiconducting properties: Semiconducting properties refer to the unique ability of certain materials to conduct electricity under specific conditions, making them essential for electronic devices. These materials typically exhibit conductivity that falls between that of conductors and insulators, enabling their use in applications such as transistors, diodes, and photovoltaic cells. Understanding the periodic table and elemental properties helps identify which elements can exhibit these semiconducting characteristics, particularly those found in groups 14 and 16.
Shielding effect: The shielding effect refers to the phenomenon where inner electrons in an atom repel outer electrons, reducing the effective nuclear charge that outer electrons experience. This effect influences atomic size, ionization energy, and electronegativity, ultimately playing a crucial role in determining elemental properties and periodic trends.
Transition metals: Transition metals are a group of metallic elements located in the d-block of the periodic table, known for their ability to form variable oxidation states and complex ions. They typically have partially filled d-orbitals, which contribute to their unique chemical properties, including catalytic activity and the formation of colored compounds.
Trends: Trends refer to the predictable patterns or behaviors observed in the properties of elements as one moves across a period or down a group in the periodic table. These trends are essential for understanding how elements interact, their chemical properties, and their placement in the table, reflecting the underlying principles of atomic structure and periodicity.
Variable Oxidation States: Variable oxidation states refer to the ability of certain elements, particularly transition metals and some main group elements, to exhibit multiple oxidation states in their compounds. This characteristic allows these elements to participate in a variety of chemical reactions and form diverse compounds, playing a crucial role in their reactivity and properties.
Actinides
See definition

Actinides are a series of 15 chemical elements in the periodic table, ranging from actinium (Ac, atomic number 89) to lawrencium (Lr, atomic number 103). They are known for being heavy, radioactive metals that display similar properties and are often found in the bottom row of the f-block in the periodic table, indicating their connection to elemental properties like oxidation states and electron configurations.

Term 1 of 39

Key Terms to Review (39)

Actinides
See definition

Actinides are a series of 15 chemical elements in the periodic table, ranging from actinium (Ac, atomic number 89) to lawrencium (Lr, atomic number 103). They are known for being heavy, radioactive metals that display similar properties and are often found in the bottom row of the f-block in the periodic table, indicating their connection to elemental properties like oxidation states and electron configurations.

Term 1 of 39

Actinides
See definition

Actinides are a series of 15 chemical elements in the periodic table, ranging from actinium (Ac, atomic number 89) to lawrencium (Lr, atomic number 103). They are known for being heavy, radioactive metals that display similar properties and are often found in the bottom row of the f-block in the periodic table, indicating their connection to elemental properties like oxidation states and electron configurations.

Term 1 of 39



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AP® and SAT® are trademarks registered by the College Board, which is not affiliated with, and does not endorse this website.