What are the elements which are liquids at room temperature and standard pressure ? 1. Helium 2. Mercury 3. Chlorine 4. Bromine Select the correct answer using the code given below :

At standard room temperature (25°C) and pressure (1 atm), only two elements on the periodic table exist in a liquid state: Mercury (Hg) and Bromine (Br) [2]. Mercury is the only metal that is liquid at room temperature, commonly used in thermometers [3]. Bromine is a non-metal that also exists as a liquid under these conditions. In contrast, Helium is a noble gas that only becomes liquid at extremely low temperatures, approximately -269°C [4]. Chlorine is a halogen that exists as a gas at room temperature and standard pressure. While other elements like Gallium or Cesium can melt near room temperature, they are technically solids at the standard 25°C reference point. Therefore, only Mercury (2) and Bromine (4) satisfy the criteria.

Sources

1. [2] Science , class X (NCERT 2025 ed.) > Chapter 3: Metals and Non-metals > Table 3.1 > p. 39
2. [3] Science-Class VII . NCERT(Revised ed 2025) > Chapter 4: The World of Metals and Non-metals > Table 4.1: Appearance, hardness, and eff ect of hammering on diff erent objects or materials > p. 43
3. [4] https://en.wikipedia.org/wiki/Liquid_helium