Elements and the Periodic Table: Structure, Classification, and Chemical Symbols

Elements and the Periodic Table

Introduction

The study of elements and the periodic table is foundational in general, organic, and biological (GOB) chemistry. Understanding the structure, classification, and properties of elements enables students to predict chemical behavior and navigate the periodic table effectively.

Elements

Definition and Key Characteristics

• Element: A pure substance from which all other substances are built. Elements cannot be broken down into simpler substances by chemical means.

• There are 118 different kinds of elements known; 88 occur naturally and make up all substances in the world.

• Each element is represented by a unique chemical symbol (one or two letters).

• Example: Sulfur is an example of an element.

Chemical Symbols

• The first letter of a chemical symbol is always capitalized; the second letter (if present) is lowercase.

• Some symbols are derived from Latin or Greek names (e.g., Fe for iron from ferrum).

• If two letters are both capitalized, it represents two different elements combined chemically (not a single element symbol).

Common Element Chemical Symbols

The following table lists common elements and their chemical symbols:

Name	Symbol	Name	Symbol	Name	Symbol
Aluminum	Al	Gallium	Ga	Oxygen	O
Argon	Ar	Gold (aurum)	Au	Phosphorus	P
Arsenic	As	Helium	He	Platinum	Pt
Barium	Ba	Hydrogen	H	Potassium (kalium)	K
Boron	B	Iodine	I	Radium	Ra
Bromine	Br	Iron (ferrum)	Fe	Silicon	Si
Cadmium	Cd	Lead (plumbum)	Pb	Silver (argentum)	Ag
Calcium	Ca	Lithium	Li	Sodium (natrium)	Na
Carbon	C	Magnesium	Mg	Strontium	Sr
Chlorine	Cl	Manganese	Mn	Sulfur	S
Chromium	Cr	Mercury (hydrargyrum)	Hg	Tin (stannum)	Sn
Cobalt	Co	Neon	Ne	Titanium	Ti
Copper (cuprum)	Cu	Nickel	Ni	Uranium	U
Fluorine	F	Nitrogen	N	Zinc	Zn

The Periodic Table

Structure and Organization

• The Periodic Table organizes all known elements by increasing atomic number and recurring chemical properties.

• Elements are arranged in periods (horizontal rows) and groups (vertical columns).

Periods

• Each horizontal row is called a period.

• There are 7 periods, numbered from top to bottom.

• Period 1 contains 2 elements; Periods 2 and 3 contain 8 elements each; Periods 4 and 5 contain 18 elements each; Periods 6 and 7 contain 32 elements each.

Groups

• Each vertical column is called a group or family of elements, sharing similar properties.

• Groups are numbered 1–18 (modern system) or 1A–8A and 1B–8B (older system).

• Representative elements are found in Groups 1A–8A; transition elements are in the center (Groups 3–12); inner transition elements (lanthanides and actinides) are placed below the main table.

Names and Properties of Selected Groups

Group	Old Name	Modern Name	Key Properties
1	1A	Alkali Metals	Soft, shiny, highly reactive metals; good conductors; low melting points; react vigorously with water; form white products with oxygen.
2	2A	Alkaline Earth Metals	Shiny, less reactive than Group 1; not as soft; higher melting points.
17	7A	Halogens	Highly reactive nonmetals; form compounds with most elements.
18	8A	Noble Gases	Very unreactive; rarely form compounds; gases at room temperature.

Classification of Elements

Metals, Nonmetals, and Metalloids

• Metals: Located on the left and center of the periodic table; typically shiny, malleable, ductile, and good conductors of heat and electricity.

• Nonmetals: Found on the right side; generally not shiny, poor conductors, and can be gases, liquids, or brittle solids.

• Metalloids: Elements with properties intermediate between metals and nonmetals; found along the zigzag line (staircase) on the periodic table.

Health and Essential Elements

Essential Elements for Health

• Certain elements are essential for human health, including oxygen (O), carbon (C), hydrogen (H), nitrogen (N), calcium (Ca), phosphorus (P), and others.

• Trace elements such as iron (Fe), zinc (Zn), and iodine (I) are required in small amounts for proper physiological function.

Examples and Applications

• Example: Mercury (Hg) is a silvery, shiny element that is a liquid at room temperature. It can enter the body through inhalation, skin contact, or ingestion of contaminated food and water.

• Application: Understanding chemical symbols and periodic table organization is essential for interpreting chemical formulas and reactions in GOB chemistry.

Practice Questions

• Write the correct chemical symbols for: Iodine (I), Iron (Fe), Magnesium (Mg), Zinc (Zn), Lithium (Li).

• Give the names of the elements with these symbols: P (Phosphorus), Ba (Barium), Mn (Manganese), Be (Beryllium).

Additional info: The periodic table image and chemical symbol table are referenced from Timberlake, K. (2018). Chemistry: Introduction to general, organic and biological chemistry (13th ed.). Pearson Education.