Organization of the Periodic Table

Organization of the Periodic Table

• The periodic table is organized into groups (vertical columns) labeled #1-18, where elements in the same group share similar chemical properties due to identical valence electron counts.
• Periods (horizontal rows) are numbered #1-7, indicating the highest principal energy shell occupied by elements.

Types of Elements

• Metals constitute the majority of the periodic table, situated to the left of the 'staircase'.
• Nonmetals are fewer in number and exhibit a wider variation in properties compared to metals.
• Semi-metals, or metalloids, possess characteristics of both metals and nonmetals.

Properties of Metals

• Most metals are solid (except for Mercury), malleable, ductile, hard, lustrous, and excellent conductors of heat and electricity.
• Metals tend to lose electrons, forming positive ions.
• Metallic properties increase moving down a group and decrease across a period, with Francium being the most metallic.

Properties of Nonmetals

• Most nonmetals are gases in their natural form (except Bromine, a liquid), exhibit brittleness, and are nonmalleable and nondductile.
• Nonmetals lack luster, are poor conductors of heat and electricity, and gain electrons to form negative ions.

Transition Metals

• Transition metals, found in Groups 3-12, are known for forming colorful ions.
• Properties include high melting points (except Mercury), the capacity to form colored ions, and a variable number of valence electrons removed from p and d sublevels. They are generally less reactive than Groups 1 and 2 metals.

Rare Earth Metals

• Lanthanide Series encompasses elements with atomic numbers 58-71 and is commonly referred to as rare earth metals.
• Actinide Series includes elements with atomic numbers 90-103, most of which are radioactive and synthetically produced.

Noble Gases

• Group 18 contains noble gases that are inert due to having a full valence shell.
• Helium, despite having only 2 valence electrons, is classified as a noble gas.

Alkali and Alkaline Earth Metals

• Alkali Metals (Group 1) are the most reactive metals, with Francium as the most reactive.
• Alkaline Earth Metals (Group 2) are the second most reactive set of metals.

Halogens

• Halogens are found in Group 17 and are recognized as the most reactive nonmetals.

Physical States of Elements

• Most elements naturally exist as solids; notable exceptions include Mercury (liquid) and gases such as Hydrogen, Nitrogen, Oxygen, Fluorine, Chlorine, and all noble gases.

Diatomic Elements

• Certain elements exist as diatomic molecules in nature, including Bromine, Iodine, Nitrogen, Chlorine, Hydrogen, Oxygen, and Fluorine.

Electron Configuration and Block Designation

• The periodic table is divided into blocks: S block (Groups 1&2), P block (Groups 13-18), D block (Groups 3-12), and F block (Lanthanide & Actinide series).

Allotropes

• Different structural forms of nonmetals that coexist in the same physical state due to variations in atomic bonding and arrangement, leading to distinct physical and chemical properties.

Atomic Trends

• Metallic character increases down a group and decreases across a period.
• Atomic radius increases down a group as additional energy levels are added, while it decreases across a period due to increased nuclear charge attracting electrons more closely.

Ionization Energy

• Ionization energy (IE) refers to the energy required to remove an electron from an atom.
• IE decreases down a group as more energy levels lead to easier electron removal and increases across a period due to greater nuclear attraction as protons are added.

Electronegativity

• Electronegativity is a measure of an atom's ability to attract and bond with electrons. It generally increases across a period and decreases down a group.