The most metallic element in the fifth peroid is

Options

A. silver
B. rubidium
C. gold
D. rhodium

Answer

To determine the most metallic element in the fifth period of the periodic table, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Elements in the Fifth Period**:
The fifth period of the periodic table includes the following elements:
- Group 1: Rubidium (Rb)
- Group 2: Strontium (Sr)
- Group 3: Yttrium (Y)
- Group 4: Zirconium (Zr)
- Group 5: Niobium (Nb)
- Group 6: Molybdenum (Mo)
- Group 7: Technetium (Tc)
- Group 8: Ruthenium (Ru)
- Group 9: Rhodium (Rh)
- Group 10: Palladium (Pd)
- Group 11: Silver (Ag)
- Group 12: Cadmium (Cd)
- Group 13: Indium (In)
- Group 14: Tin (Sn)
- Group 15: Antimony (Sb)
- Group 16: Tellurium (Te)
- Group 17: Iodine (I)
- Group 18: Xenon (Xe)

2. **Understand the Concept of Metallic Character**:
Metallic character refers to the tendency of an element to lose electrons and form positive ions (cations). Metals are generally electropositive, meaning they can easily lose their valence electrons.

3. **Analyze the Trend of Metallic Character in the Period**:
As we move from left to right across a period in the periodic table, the metallic character decreases. This is due to the increase in nuclear charge (number of protons) which holds the valence electrons more tightly, making it harder for the element to lose electrons.

4. **Locate the Most Metallic Element**:
In the fifth period, Rubidium (Rb) is located at the far left, making it the most metallic element in this period. As we move right from Rubidium to Strontium and then to the transition metals, the metallic character decreases.

5. **Conclusion**:
Therefore, the most metallic element in the fifth period is **Rubidium (Rb)**.