Write complete chemical formula, including physical state symbol, for each element listed below in its standard state: first row of the table has been completed for you element formula Fe (s) uranium Chlorine sulfur
The Correct Answer and Explanation is:
| Element | Formula (Standard State) |
|---|---|
| Fe (iron) | Fe (s) |
| Uranium | U (s) |
| Chlorine | Cl₂ (g) |
| Sulfur | S₈ (s) |
Explanation
In chemistry, the standard state of an element refers to its most stable physical form at 1 atmosphere pressure and 25°C (298 K). This state is used as a reference point for thermodynamic calculations like enthalpy and Gibbs free energy.
Let’s analyze each element:
- Iron (Fe):
Iron is a transition metal and exists in its standard state as a solid metal. It has a metallic crystalline structure and is represented simply as Fe (s). This means pure elemental iron in solid form. - Uranium (U):
Uranium, another metallic element, is also a solid in its standard state. It is dense, silvery-gray, and slightly radioactive. Like iron, it exists as U (s) — the elemental form in the solid phase. - Chlorine (Cl₂):
Chlorine is a non-metal and is diatomic in its elemental form. This means it naturally exists as molecules made of two chlorine atoms. At room temperature and standard pressure, chlorine is a greenish-yellow gas, and its formula is Cl₂ (g). The subscript “2” shows its diatomic nature, and “(g)” represents the gas phase. - Sulfur (S₈):
Sulfur is a non-metal and occurs in nature primarily as S₈, which is a cyclic molecule containing eight sulfur atoms. At room temperature, sulfur is a yellow solid, so its standard state is written as S₈ (s). This form is more stable than S or S₂ under standard conditions.
In conclusion, the standard state reflects the most stable and commonly found form of an element under standard conditions. Each element can have different molecular structures (like monoatomic, diatomic, or polyatomic) and physical states (solid, liquid, or gas), depending on its chemical nature and bonding.
