Elements, Symbols, and Classification of Matter – Week 1 Study Notes

Elements and Symbols

Definition of Elements

Elements are pure substances from which all other substances are made. They cannot be broken down into simpler substances by chemical means. Each element is represented by a unique chemical symbol and is listed on the periodic table.

• Element: A substance composed of only one type of atom.

• Example: Magnesium (Mg) is an element that consists only of magnesium atoms.

Naming Elements

Element names are derived from various sources, including planets, mythological figures, minerals, geographic locations, and famous people.

Element	Symbol	Source of Name
Uranium	U	The planet Uranus
Thallium	Tl	Titans (mythology)
Chlorine	Cl	Chloros: "greenish yellow" (Greek)
Iodine	I	Ioiedes: "violet" (Greek)
Magnesium	Mg	Magnesia, a mineral
Californium	Cf	California
Curium	Cm	Marie and Pierre Curie
Copernicium	Cn	Nicolaus Copernicus

Chemical Symbols

Chemical symbols are abbreviations used to represent the names of elements. They consist of one or two letters, always starting with a capital letter.

• One-Letter Symbols: C (carbon), N (nitrogen), F (fluorine), O (oxygen)

• Two-Letter Symbols: Co (cobalt), Ca (calcium), Al (aluminum), Mg (magnesium)

Names and Symbols of Common Elements

Many elements have symbols derived from their English or Latin names. Some common examples are listed below:

Name*	Symbol	Name*	Symbol
Aluminum	Al	Gallium	Ga
Gold (aurum)	Au	Oxygen	O
Iron (ferrum)	Fe	Potassium (kalium)	K
Lead (plumbum)	Pb	Silver (argentum)	Ag
Sodium (natrium)	Na	Tin (stannum)	Sn
Mercury (hydrargyrum)	Hg	Phosphorus	P
Magnesium	Mg	Carbon	C
Nitrogen	N	Zinc	Zn

Additional info: Names in parentheses are ancient Latin or Greek words from which the symbols are derived.

Chemical Symbols from Latin Names

Some elements have symbols based on their Latin names, which may differ from their English names.

• Silver: Symbol Ag, from argentum

• Gold: Symbol Au, from aurum

Classification of Matter

Definition of Matter

Matter is anything that has mass and occupies space. All substances and materials are forms of matter.

Pure Substances vs. Mixtures

Matter can be classified based on its composition:

• Pure Substances: Have a fixed or definite composition. They can be elements or compounds.

• Mixtures: Contain two or more substances physically mixed but not chemically combined. The composition can vary.

Elements and Compounds

• Element: Composed of only one type of atom (e.g., copper, Cu).

• Compound: Composed of two or more elements chemically combined in a fixed ratio (e.g., water, $H_2O$; sodium chloride, $NaCl$).

Mixtures

• Mixture: Contains two or more substances physically mixed. Can be separated by physical methods.

• Example: A mixture of sand and water can be separated by filtration.

Types of Mixtures

• Homogeneous Mixture: Composition is uniform throughout; different parts are not visible. Also called a solution. Example: Brass (copper and zinc), air, salt water.

• Heterogeneous Mixture: Composition varies from one part to another; different parts are visible. Example: Salad, sand and water, granite.

The Periodic Table

Organization of the Periodic Table

The periodic table organizes elements into groups (vertical columns) and periods (horizontal rows) based on their properties and atomic number.

• Groups: Vertical columns containing elements with similar properties. Numbered 1-18 (modern system) or 1A-8A and 3B-12B (older system).

• Periods: Horizontal rows numbered 1-7.

Group Names and Types of Elements

• Alkali Metals: Group 1A (1) – e.g., lithium (Li), sodium (Na), potassium (K)

• Alkaline Earth Metals: Group 2A (2) – e.g., beryllium (Be), magnesium (Mg), calcium (Ca)

• Halogens: Group 7A (17) – e.g., fluorine (F), chlorine (Cl), bromine (Br), iodine (I)

Metals, Nonmetals, and Metalloids

The periodic table is divided by a heavy zigzag line:

• Metals: Located to the left of the zigzag line. Shiny, ductile, good conductors of heat and electricity, mostly solids (except mercury).

• Nonmetals: Located to the right of the zigzag line. Dull, brittle, poor conductors, good insulators, low densities and melting points.

• Metalloids: Located along the zigzag line. Exhibit properties of both metals and nonmetals. Used as semiconductors and insulators.

Comparison Table: Metal, Metalloid, Nonmetal

Property	Metal (Antimony, Sb)	Metalloid (Sulfur, S)	Nonmetal
Appearance	Shiny	Dull yellow	Dull
Ductility	Ductile	Brittle	Brittle
Malleability	Hammered into sheets	Shatters when hammered	Shatters when hammered
Conductivity	Good conductor	Poor conductor	Poor conductor, good insulator
Uses	Jewelry, coins	Harden lead, color glass	Gunpowder, rubber, fungicides
Density	10.5 g/mL	2 g/mL	Low
Melting Point	962°C	113°C	Low

Elements Essential to Health

Major Elements in the Human Body

• Oxygen, carbon, hydrogen, and nitrogen make up about 96% of body mass.

• Most hydrogen and oxygen are found as water, which constitutes 55-60% of body mass.

Minerals Essential for Health

• Calcium (Ca), phosphorus (P), potassium (K), chlorine (Cl), sulfur (S), sodium (Na), magnesium (Mg) are essential minerals.

• Functions include formation of bones and teeth, maintenance of heart and blood vessels, muscle contraction, nerve impulses, acid-base balance, and regulation of cellular metabolism.

Summary Table: Classification of Matter

Type	Description	Examples
Element	Pure substance, one type of atom	Copper (Cu), Aluminum (Al)
Compound	Pure substance, two or more elements chemically combined	Water ($H_2O$), Sodium chloride ($NaCl$)
Homogeneous Mixture	Uniform composition throughout	Brass, air, salt water
Heterogeneous Mixture	Composition varies, different parts visible	Salad, sand and water