Identify the correct pair of elements among the following which are liid at room temperature and standard pressure.

At standard room temperature (approximately 25°C) and pressure, only two elements in the periodic table exist in a liquid state: mercury and bromine. Mercury (Hg) is the only metallic element that remains liquid under these conditions, a property famously utilized in thermometers [2]. Bromine (Br) is a non-metal belonging to the halogen group and is the only non-metallic element that is liquid at room temperature. While other elements like rubidium, gallium, and cesium have low melting points, they remain solid at standard room temperature and only liquefy at slightly higher temperatures. Fluorine is a gas, and thallium is a solid metal at room temperature. Therefore, the correct pair of elements that are liquid at room temperature and standard pressure is bromine and mercury.

Sources

1. [1] 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
2. [2] Science , class X (NCERT 2025 ed.) > Chapter 3: Metals and Non-metals > What you have learnt > p. 55