Question

The elements which exist in the liquid state at room temperature are 1\. Na 2\. Br 3\. \(\mathrm{Hg}\) 4\. Ga (a) \(1,2,3\) (b) 2,3 (c) 2,4 (d) \(1,2,3\)

Short answer

(b) 2,3

Step-by-step solution

Understanding the Problem

The problem asks us to identify which of the given elements exist in the liquid state at room temperature. We have four options to choose from.

Recall Room Temperature States

Most elements exist as solids at room temperature (approximately 25°C or 298K), but a few can be liquids. Known elements that are liquid at room temperature include Bromine (Br) and Mercury (Hg).

Check Each Element

- **Sodium (Na)**: A metal that is solid at room temperature. - **Bromine (Br)**: A halogen that exists as a liquid at room temperature. - **Mercury (Hg)**: A metal that is liquid at room temperature. - **Gallium (Ga)**: Although Gallium can melt slightly above room temperature, it is generally solid at standard room temperature. Thus, it does not qualify as liquid in this context.

Match with Answer Choices

Considering the above facts, Bromine (Br) and Mercury (Hg) are the elements from the list that are liquid at room temperature. Looking at the choices, option (b) which is 2,3 corresponds to Br and Hg.

Key concepts

Bromine

Bromine is a fascinating and unique element. It's a member of the halogen group in the periodic table, which includes other elements like chlorine, fluorine, and iodine. Bromine is particularly distinct because it is one of the very few elements that is a liquid at room temperature, around 25°C or 298K. This reddish-brown element has a pungent smell and is highly reactive. Because of its reactivity, bromine is rarely found in nature in its elemental form. Instead, it usually occurs as bromide compounds.

At room temperature, bromine exists as a dense, corrosive liquid. It can vaporize easily, forming dangerous vapors that can be harmful if inhaled. When working with bromine, it's essential to take safety precautions due to its toxic nature. In everyday applications, bromine is used in manufacturing flame retardants, certain types of medication, and water treatment chemicals.

Despite its relatively rare liquid state among the elements, bromine's chemical properties make it invaluable in many industrial processes. Its ability to participate in a wide array of chemical reactions highlights its versatility, although it must be handled with care due to its potential hazards.

Mercury

Mercury is another intriguing element that exists as a liquid at room temperature, similar to bromine. However, unlike bromine, mercury is a metal. In fact, it is the only metal that remains liquid at standard conditions for temperature and pressure. This shiny, silvery element is also known as quicksilver and has been used for centuries in various applications.

In the periodic table, mercury is part of the group 12 elements, which also include zinc and cadmium. One of the reasons mercury is liquid at room temperature is due to its weak metallic bonding. The electrons in mercury atoms don't bind strongly together, allowing them to flow more freely, which leads to its liquid state.

Mercury has several important uses, particularly in scientific equipment like thermometers and barometers. Its ability to conduct electricity also makes it useful in electrical switches and relays. However, it's crucial to note that mercury is highly toxic, and its vapors can be harmful when inhaled. Severe exposure to mercury can lead to mercury poisoning, which affects the nervous system and other organs. Because of its toxicity, the use of mercury has significantly declined, and safer alternatives are often sought in industries.

Room Temperature

Room temperature is an important reference point in both chemistry and everyday life. It typically refers to a comfortable indoor temperature for humans, which is around 20°C to 25°C (68°F to 77°F). For scientific experiments and industrial processes, room temperature is often defined more precisely as approximately 25°C (298K).

Understanding room temperature helps us predict and explain the states of various elements and compounds under typical conditions. Most elements are solid at room temperature because they have tightly packed atomic structures with strong bonds. Nevertheless, a few exceptions, like bromine and mercury, challenge this typical behavior by existing as liquids.

In scientific contexts, room temperature is used as a standard for measuring and comparing the properties of substances. For instance, discovering an element that is liquid at room temperature provides insights into its atomic structure and bonding. It also impacts how scientists and engineers handle and utilize such substances in practical applications. Recognizing the behavior of elements at room temperature helps in designing processes, creating products, and enhancing safety protocols across fields.