Answer:
Solid: calcium and potassium
Liquid: mercury and bromine
Gaseous: oxygen and fluorine
Step-by-step explanation:
Matter exists in three different states namely: solid, gaseous and liquid. Elements that are found in nature are classified as matter. Since, these elements are grouped as matter, they can either be found as either solids, liquids or gases at normal temperature and pressure.
At normal temperature (20°C or 293K) and pressure (1 atm), the following elements are found to exists in the respective state of matter:
Solid: Calcium (Ca) and potassium (K)
Liquid: Mercury (Hg) and bromine (Br)
Gaseous: Oxygen (O) and fluorine (F)