Elements-and-the-Periodic-Table. IGCSE 7

IGCSE 7 CHEMISTRY

1. Elements and the Periodic Table Explore the fundamental building blocks of matter and discover how elements organize into the periodic table that governs our universe.

2. What Are Elements? Definition A substance that cannot be split into other substances. Each element has its own unique particles and properties. Universal Building Blocks Every material on Earth and everything in the Universe is made from particles of one or more elements. Over 100 Elements There are more than 100 special substances called elements, each with distinct characteristics.

3. Platinum: A Valuable Element Why So Expensive? In 2020, 1 kg of platinum cost over $33,000 USD due to its unique properties and important applications. Medical Uses Surgeons insert platinum-containing stents into blood vessels to keep them open. Catalytic Converters Convert harmful exhaust gases to less harmful ones in cars. Ancient Jewelry South Americans crafted platinum and gold jewelry 2000 years ago.

4. The Periodic Table The periodic table lists all elements in a specific order, grouping together elements with similar properties. Metals vs Non-Metals A stepped line divides elements into metals (left side) and non-metals (right side). Common Elements Hydrogen is most common in the Universe. Carbon makes up all living things including you.

5. Discovering Elements Through History 1 Ancient Times Early humans found sulfur near volcanoes, made charcoal from wood, and discovered gold in stream beds. 2 7000 Years Ago People extracted copper from rocks to make weapons, tools, and jewelry. 3 1200-1700s Scientists discovered zinc in India and phosphorus from urine evaporation. 4 1800s Over 50 elements discovered using new technology like the spectroscope. 5 20th Century Scientists created more than 25 artificial elements and filled remaining gaps.

6. Chemical Symbols Scientists worldwide use the same one- or two-letter codes for elements, making communication universal. 1 Writing Rules Capital letter for one-letter symbols (N for nitrogen). Capital + lowercase for two letters (Mg for magnesium). 2 Language Origins Some symbols come from Latin (Fe for iron from ferrum) or German (W for tungsten from Wolfram). 3 Universal Language All scientists recognize S as sulfur, regardless of their native language.

7. Atoms: The Smallest Particles Incredibly Tiny An atom is the smallest particle of an element that can exist. Their diameter is about 0.000 000 01 cm. 100M Atoms per cm If placed side by side, 100 million atoms would stretch one centimeter. 100 Element Types About 100 elements exist, meaning 100 different types of atoms.

8. Compounds: When Elements Join A compound is made of atoms from two or more elements strongly joined together, creating entirely new properties. Tooth Enamel Contains calcium, phosphorus, and oxygen atoms joined as calcium phosphate. Water Properties H₂O is liquid at 20°C and puts out fires, unlike its gaseous elements. Carbon Monoxide (CO) One carbon + one oxygen atom. Poisonous gas. Carbon Dioxide (CO₂) One carbon + two oxygen atoms. Non-poisonous greenhouse gas.

9. Mixtures vs Compounds Understanding the key differences between mixtures and compounds helps explain material properties. Mixtures Substances not joined together Keep original properties Easy to separate Variable amounts Compounds Atoms strongly joined New properties formed Difficult to separate Fixed proportions Example: Iron + sulfur mixture can be separated by magnet. Iron sulfide compound cannot be easily separated and has different properties.

10. Elements in Living Things Your body contains enough hydrogen to fill a classroom and enough carbon to make countless pencils! 65% Oxygen Most abundant element in human body 18% Carbon Essential for all organic compounds 10% Hydrogen Found in water and organic molecules 3% Nitrogen Key component of proteins and DNA These elements combine to form compounds like proteins, fats, carbohydrates, and vitamins essential for life.