At room temperature, what is the state of each of the following? If necessary, look up the information in a reference source. (a) hydrogen (c) nitrogen (b) aluminum (d) mercury

Chemical elements are pure substances that consist of only one type of atom, distinguished by its atomic number which represents the number of protons in its nucleus. They are the building blocks of matter and cannot be broken down into simpler substances by chemical means. Each element has its own unique physical and chemical properties, which dictate its behavior in chemical reactions and its state at room temperature. For instance, hydrogen (H), with atomic number 1, is the lightest and most abundant element in the universe, often found as a diatomic gas at room temperature.

Understanding the properties of elements is critical for establishing their state under different conditions. Elements like aluminum (Al), with atomic number 13, show metallic characteristics such as ductility and malleability and are typically found in a solid state at room temperature.

Room temperature, generally accepted as around 20 to 25 degrees Celsius (68 to 77 degrees Fahrenheit), is a standard benchmark for describing the natural state of substances on Earth. The properties of chemical elements at room temperature, such as state (solid, liquid, or gas), melting point, and boiling point, are crucial for countless applications. For instance, mercury (Hg), with atomic number 80, is a rare exception among metals as it remains a liquid at room temperature, making it valuable for devices like thermometers.

The states of matter at room temperature influence how elements are handled, stored, and used in industry and research. Hence, an in-depth knowledge of these properties is essential for chemists and engineers, and even in everyday decision-making, like storing food or handling materials safely.

Some chemical elements exist naturally as diatomic molecules, meaning they are composed of two atoms of the same element bonded together. At room temperature, several elements form diatomic gases, including hydrogen (H₂) and nitrogen (N₂), which comprise the two simplest and most abundant diatomic gases in the Earth's atmosphere.

Diatomic molecules are held together by covalent bonds, where atoms share electrons. The stability of diatomic gases at room temperature is a result of the bond strength between the atoms and the kinetic energy of molecules. This state is significant for life on Earth, as nitrogen helps to stabilize the atmosphere's composition, and hydrogen is vital for various chemical processes, including the formation of water.