Difference Between Bromine and Iodine

The key difference between bromine and iodine is that bromine is in the liquid state at room temperature whereas iodine is in the solid state.

Bromine and iodine are elements in the halide group or the group 17 of the periodic table. Therefore, both these elements have 7 electrons in their outermost electron shell.

CONTENTS

1. Overview and Key Difference
2. What is Bromine
3. What is Iodine
4. Similarities Between Bromine and Iodine
5. Side by Side Comparison – Bromine vs Iodine in Tabular Form
6. Summary

What is Bromine?

Bromine, denoted by Br, is a halide having the atomic number 35. And at room temperature, it is a brownish-red liquid. Its vapour is also brown colored and has a pungent odor. Moreover, it is the only nonmetal that is in the liquid state at room temperature. This liquid has Br₂ molecules. Further, it is chemically less reactive than chlorine and fluorine but is more reactive than iodine.

Some Chemical Facts about Bromine

• Symbol = Br
• Atomic number = 35
• Atomic mass = 79.904 amu
• Electron configuration = [Ar] 3d¹⁰4s² 4p⁵
• Position in periodic table =group 17, period 4
• Block = p block
• Physical state = a brownish-red liquid at room temperature
• Melting point = -7.2°C
• Boiling point = 58.8°C
• Electronegativity = 2.8 (Pauling scale)
• Oxidation states = 7, 5, 4, 3, 1, −1

Bromine is a naturally occurring nonmetal and is present in bromine-rich brine deposits in countries like USA and China. Electrolysis is the common method adopted in the extraction of this element from brine deposits. Bromine was the first element extracted from seawater. However, it is not a popular method nowadays.

What is Iodine?

Iodine (I) is a halide having the atomic number 53. And it is in the solid state at room temperature and pressure. Furthermore, it is a nonmetal in the p block of the periodic table of elements.

Some Chemical Facts about Iodine

• Symbol = I
• Atomic number = 53
• Atomic mass = 126.904 amu
• Electron configuration = [Kr] 4d¹⁰5s² 5p⁵
• Position in periodic table =group 17, period 5
• Block = p block
• Physical state = a black shiny crystalline solid at room temperature
• Melting point = 113.7°C
• Boiling point = 184.4°C
• Electronegativity = 2.66 (Pauling scale)
• Oxidation states = 7, 6, 5, 4, 3, 1, −1

Although it is a shiny black crystal at room temperature, iodine forms a violet vapor when boiled. Moreover, these crystals are less soluble in water but are highly soluble in nonpolar solvents such as hexane.

Iodine is available in seawater in the form of iodide ion (I^–) but in trace amounts. At present, iodate minerals and natural brine deposits are the most common source of iodine.

What are the Similarities Between Bromine and Iodine?

• Both Bromine and Iodine are nonmetals.
• Also, both are halogens.
• Moreover, both are p block elements too.
• Both elements are composed of seven valence electrons.
• Both have -1 stale oxidation states.
• They both are less reactive than chlorine and fluorine.

What is the Difference Between Bromine and Iodine?

Summary – Bromine vs Iodine

Bromine and iodine are halides; in other words, they are chemical elements found in group 17 of the periodic table of elements. The key difference between bromine and iodine is that bromine is a liquid at room temperature while iodine is a solid at room temperature.

Reference:

1. “Bromine – Element Information, Properties and Uses | Periodic Table.” Royal Society of Chemistry, Available here.
2. “Bromine.” Wikipedia, Wikimedia Foundation, 13 Apr. 2018, Available here.
3. “Iodine – Element Information, Properties and Uses | Periodic Table.” Royal Society of Chemistry, Available here.

Image Courtesy:

1. “Bromine vial in acrylic cube” By Alchemist-hp (pse-mendelejew.de) – Own work (CC BY-SA 3.0 de) via Commons Wikimedia
2. “Iodinecrystals” By Greenhorn1 – Own work (Public Domain) via Commons Wikimedia