Difference Between Rhodium and Silver

Main Difference – Rhodium vs Silver

Rhodium and silver are two d block elements that are in the period 5 of the periodic table of elements. Rhodium is a very hard metal that has very high melting and boiling points. It has a similar appearance to silver but has very different chemical properties. Silver is a very lustrous and a precious metal, known since ancient times. The main difference between rhodium and silver is that rhodium is a very hard metal whereas silver is a soft metal.

Key Areas Covered

1. What is Rhodium (Rh)
– Definition, Chemical Properties, Characteristics
2. What is Silver (Ag)
– Definition, Chemical Properties, Characteristics
3. What are the Similarities Between Rhodium and Silver
– Outline of Common Features
4. What is the Difference Between Rhodium and Silver
– Comparison of Key Differences

Key Terms: Aqua Regia, Corrosion Resistance, Isotope, Noble Metal, Platinum Group, Reflectivity, Rhodium (Rh), Silver (Ag)

What is Rhodium

Rhodium is a chemical element having the symbol Rh and atomic number 45. It is a hard metal having a shiny-silvery appearance. An important property of Rhodium is its corrosion resistance. Hence, it is considered as a noble metal (noble metals are metallic elements that are resistant to corrosion and oxidation). Some important chemical properties of Rhodium are listed below.

Chemical symbol – Rh
Atomic number – 45
Atomic mass – 102.91 amu
Electron configuration – [Kr] 4d⁸5s¹
Block – d block
Melting point – 1963°C
Boiling point – 3695°C

Rhodium belongs to the Platinum group of metals. (Rhodium, along with, Palladium, ruthenium, osmium, iridium, and platinum, is called the platinum group metals). Rhodium has only one naturally occurring isotope; ¹⁰³Rh. It is found as the free metal in nature.

Figure 1: Rhodium Metal

Rhodium is very hard as a metal; hence it is highly durable. It has a high reflectance (the measure of the proportion of light or other radiation striking a surface which is reflected off it). Rhodium metal does not easily form an oxide, even when it is heated. Rhodium is resistant to most strong acids such as nitric acid, but is slightly soluble in aqua regia.

What is Silver

Silver is a chemical element having the chemical symbol Ag and atomic number 47. The symbol Ag is derived from its Latin name Argentum. Silver is a soft metal with a white, lustrous appearance. This metal shows the highest electrical conductivity, thermal conductivity, and reflectivity. Some important chemical properties of silver are given below.

Chemical symbol – Ag
Atomic number – 47
Atomic mass – 107.87 amu
Electron configuration – [Kr] 4d¹⁰ 5s¹
Block – d block
Melting point – 961.78 °C
Boiling point – 2162 °C

Silver is positioned in the group 11 and period 5 of the periodic table of elements. This metal is found naturally as the free, pure element. Sometimes it can be found as an alloy with gold. Naturally occurring silver has two stable isotopes; ¹⁰⁷Ag and ¹⁰⁹Ag along with some unstable isotopes.

Figure 2: Silver Coins

The properties of silver are much related to those of gold and copper. As a metal, silver is extremely soft. It is a highly ductile and malleable metal. Silver has a brilliant luster. The very high thermal and electrical conductance is due to the presence of one s orbital electron which exists as a free electron (without any interactions with d shell electrons).

Similarities Between Rhodium and Silver

Both rhodium and silver are d block elements.
Both rhodium and silver are metals.
Both rhodium and silver have shiny metallic appearance.
Both rhodium and silver are in the period 5 of the periodic table of elements.

Definition

Rhodium: Rhodium is a chemical element having the symbol Rh and atomic number 45.

Silver: Silver is a chemical element having the chemical symbol Ag and atomic number 47.

Hardness

Rhodium: Rhodium is a very hard metal.

Silver: Silver is a soft metal.

Atomic Number

Rhodium: The atomic number of rhodium is 45.

Silver: The atomic number of silver is 47.

Melting Point and Boiling Point

Rhodium: Melting point of rhodium is 1963°C and boiling point is 3695°C.

Silver: Melting point of silver is 961.78 °C and boiling point is 2162 °C.

Isotopes

Rhodium: Rhodium has only one stable isotope;¹⁰³Rh.

Silver: Silver has two stable isotopes;¹⁰⁷Ag and ¹⁰⁹Ag.

Oxide Formation

Rhodium: Rhodium does not form oxides easily, even when heated.

Silver: Silver forms unstable oxides when reacted with strong oxidizing agents.

Conclusion

Rhodium and silver are d block elements. They are metals having a lustrous, shiny appearance that is somewhat similar to each other. The main difference between rhodium and silver is that rhodium is a very hard metal whereas silver is a soft metal.

Reference:

1. “Water Treatment Solutions.” Lenntech Water treatment & purification, Available here.
2. “Rhodium – Element information, properties and uses | Periodic Table.” Royal Society of Chemistry, Available here.
3. “Silver.” Wikipedia, Wikimedia Foundation, 6 Feb. 2018, Available here.
4. “Rhodium.” Wikipedia, Wikimedia Foundation, 5 Feb. 2018, Available here.

Image Courtesy:

1. “Rhodium (Rh)” By Hi-Res Images ofChemical Elements – (CC BY 3.0) via Commons Wikimedia
2. “935216” (CC0) via pxhere