Elements in the Real World
The periodic table is not just an academic curiosity — its elements are the building blocks of every technology, medicine, and material that shapes our daily lives. This lesson explores how elements are applied across technology, medicine, industry, and the environment, and highlights some famous discoveries along the way.
Elements in Technology
Silicon — The Heart of the Digital Age
Silicon (Si, Z = 14) is the foundation of the entire electronics industry. Every smartphone, laptop, server, and digital device relies on silicon-based semiconductor chips.
- Microprocessors — Intel, AMD, Apple, and other chip manufacturers fabricate transistors on ultra-pure silicon wafers
- A modern processor may contain over 50 billion transistors, each just a few nanometres wide
- Silicon solar cells convert sunlight into electricity — photovoltaic panels are the fastest-growing energy source globally
- Silicon carbide (SiC) is used in high-power electronics for electric vehicles and industrial motors
Lithium — Powering the Portable World
Lithium (Li, Z = 3) is the lightest metal, and its electrochemical properties make it ideal for rechargeable batteries.
- Lithium-ion batteries power smartphones, laptops, electric vehicles (Tesla, BYD, Nissan Leaf), power tools, and grid-scale energy storage
- Global lithium demand has surged — mining operations in Australia, Chile, Argentina, and China supply the growing market
- Lithium is also used in the glass and ceramics industry, and in greases for high-temperature lubrication
Rare Earth Elements — Inside Every Smartphone
A typical smartphone contains at least eight rare earth elements:
| Element | Function in a Smartphone |
|---|
| Neodymium (Nd) | Speaker and microphone magnets |
| Dysprosium (Dy) | Stabilises magnets at high temperatures |
| Praseodymium (Pr) | Vibration motor magnets |
| Terbium (Tb) | Green phosphor in display |
| Europium (Eu) | Red phosphor in display |
| Yttrium (Y) | Display backlight |
| Lanthanum (La) | Camera lens glass |
| Gadolinium (Gd) | Circuit components |
The concentration of so many critical elements in a single device highlights both the ingenuity of modern engineering and the challenge of sustainable sourcing.
Gallium and Germanium — Beyond Silicon
- Gallium arsenide (GaAs) — faster than silicon for high-frequency applications; used in 5G base stations, satellite communications, and radar systems
- Gallium nitride (GaN) — enables fast-charging power adapters (now standard for many laptops and phones)
- Germanium — used in fibre optic cables that carry 99% of international internet traffic
Tantalum and Cobalt — Capacitors and Cathodes
- Tantalum capacitors are used in nearly every electronic device — small, reliable, and high-capacitance
- Cobalt is a key component of lithium-ion battery cathodes — ethical sourcing concerns around artisanal mining in the Democratic Republic of Congo have driven research into cobalt-free batteries
Elements in Medicine
Technetium-99m — Medical Imaging Workhorse
Technetium-99m (Tc-99m) is used in over 30 million medical imaging procedures per year worldwide. It is the most commonly used radioisotope in nuclear medicine.
- Injected into the body, it accumulates in specific organs or tissues
- Gamma cameras detect the emitted radiation to produce images of bones, organs, and blood flow
- Half-life of ~6 hours — ideal for imaging (long enough to complete the scan, short enough to minimise radiation dose)
- Produced from molybdenum-99 generators in hospitals
Platinum — Cancer Treatment
- Cisplatin (cis-diamminedichloroplatinum(II)) was one of the first metal-based anti-cancer drugs
- Approved in 1978, it is still used to treat testicular, ovarian, bladder, and lung cancers
- Works by crosslinking DNA in cancer cells, preventing cell division
- Carboplatin and oxaliplatin are related platinum compounds with fewer side effects
- The discovery of cisplatin's anti-cancer properties by Barnett Rosenberg in the 1960s was accidental — he was studying the effect of electric fields on bacterial growth
Other Elements in Medicine
| Element | Medical Application |
|---|
| Iodine-131 (I) | Treatment of thyroid cancer and hyperthyroidism |
| Gadolinium (Gd) | MRI contrast agent |
| Gold (Au) | Treatment of rheumatoid arthritis (gold salts); nanoparticles in diagnostics |
| Barium (Ba) | Barium meals for X-ray imaging of the digestive tract |
| Cobalt-60 (Co) | External beam radiotherapy |
| Lutetium-177 (Lu) | Targeted radionuclide therapy for neuroendocrine tumours |
| Americium-241 (Am) | Bone density measurement |
| Titanium (Ti) | Joint replacements, dental implants, surgical plates and screws |
| Silver (Ag) | Antimicrobial wound dressings |
Elements in Industry
Iron and Steel