PERIODIC TABLE
PERIODIC TABLE
Periodic Table: Key Characteristics of Hydrogen, Helium, Lithium, Beryllium, and Boron
Hydrogen (Atomic Number 1)
Hydrogen is the lightest element and exists predominantly as a gas with the lowest density. It is highly flammable and forms explosive mixtures with air. As the most abundant substance in the universe, it is central to energy applications, notably as a clean fuel in hydrogen fuel cells where electricity is generated with only water as a by-product. Page 286.
Helium (Atomic Number 2)
Helium is the second-lightest element, characterized by an extremely low density and remarkable chemical inertness. It holds the record for the lowest boiling point of all elements, roughly -269°C, which makes it ideal for uses where cooling and non-reactivity are essential, such as in balloons and airships. Page 294.
Lithium (Atomic Number 3)
Lithium is the lightest solid metal and belongs to the alkali metal group. It is highly reactive, with low density and a soft, silvery appearance. Today, its most important application is in rechargeable lithium-ion batteries, which power a wide range of portable devices and electric vehicles. Page not specified.
Beryllium (Atomic Number 4)
Beryllium is a hard, gray metal with low density and a high melting point. It can be toxic if inhaled as dust. Its strength-to-weight ratio makes it valuable for strengthening metals, and it is used in aerospace alloys and other high-performance applications. Page not specified.
Boron (Atomic Number 5)
Boron is a metalloid exhibiting properties between metals and nonmetals, including poor electrical conductivity at room temperature. It strengthens glass and ceramics and is a key component of borosilicate glass, such as Pyrex. Page not specified.
Key takeaways
- Hydrogen and helium illustrate the broad spectrum of light elements—from highly reactive, energy-related roles to inert, ultra-light gases used for safe, non-reactive applications.
- Lithium, beryllium, and boron demonstrate how light elements contribute to modern technology: energy storage, aerospace materials, and advanced glass/ceramics.
- The first five elements highlight fundamental periodic trends (density, reactivity, and state) that underpin their practical uses in science and industry.
