Question

Name one metal and non-metal that exist in liquid state at room temperature. Name two metals having melting point less than 310 k ($30{}^\circ C$).

Answer 1

Hint: Elements are arranged in a tabular form called periodic table and there are 115 elements present in the periodic table. There are similarities as well as differences in the properties of these elements. On the basis of these properties elements can be divided into metals and non-metals.

Complete answer:
Metals are arranged on the left side of the periodic table and there are five kinds of metals: Alkaline earth metals, Alkali metals, Transition metals, Actinides and Lanthanides.
Non-metals are generally those elements which form negative ions by accepting or gaining electrons. Non-metals usually have 4, 5, 6 or 7 electrons in their outermost shell. It has high ionization energy and high electronegativity. Generally non-metals are those substances which do not follow the properties of metals like ductility, malleability, lustrous, sonorous, good conductor of heat and electricity.
All the metals are generally solid in nature but mercury is the metal which is liquid at room temperature and bromine is the non-metal which is liquid at room temperature.
Two metals which have a melting point less than 310 k ($30{}^\circ C$) are Cesium and Gallium.

Note:
There are 92 elements out of which 70 are metals. While non-metal elements are those that do not possess the properties of metal. These are arranged on the left side of the periodic table. And there are 22 non-metals in the periodic table.