Periodic Properties Of Halogens
Atomic Radii
From fluorine to iodine, the atomic radii of the halogen elements gets larger, as the atomic number increases. This is due to the increasing amount of atomic shell.
Electronegativity
Halogen elements have the greatest electronegativity value compared to other elements in the periodic table. From top to bottom, the electronegativity value of the halogen elements is getting smaller. Fluor is the element with the greatest electronegativity value among all elements in the periodic table.
Reactivity
Halogen is the most reactive non-metallic element. The reactivity of the halogen is due to its enormous electronegativity. The greater the electronegativity then the halogens will be more reactive. This is because the atom will more easily capture the electrons if the value of its electronegativity is high.
The reactivity of halogen elements decreases from fluor to iodine as the decreasing of electronegativity. Since the halogen element is highly reactive, in nature we can not find it in a free state. In nature, halogens are found in diatomic molecules
State In Standard Conditions (STP)
At room temperature, fluorine is a pale yellow gas and chlorine is a pale green gas. This color can only be seen if the concentrations of these gases are high. Bromine is a red-brown element and it is the only non-metallic element that is liquid at room temperature.
Iodine is a black solid. The iodine solid looks like a metal solid. But even so, chemically iodine shows the properties of nonmetallic elements.
The vapor pressure of bromine and iodine is quite high. Both of these compounds are usually stored in a sealed container. At the top of the bromine liquid, there will be a red-brown toxic vapor. Whereas if the iodine solid is heated gently, it will produce violet-colored toxic vapors.
Astatine is a radioactive halogen. All the astatine isotopes have a very short half-life. This makes it very difficult for a chemist to study its properties. The astatine isotope is highly unstable and releases radiation with high intensity.
However, the chemical properties of astatine follow the pattern shown by other halogen elements.
Another thing that makes chemists difficult to study this element is because astatine is the rarest element on earth. The entire crust of the earth as deep as 1 km is thought to contain only 44 mg of astatine.
Melting and Boiling Points
In nature, halogens are found in diatomic molecules. From fluorine to iodine, the melting and boiling point of the elements increases slowly. The melting and boiling points of halogens are depended on the ability of the molecule to polarize (polarizability).
Oxidation State
The oxidations state of fluorine is always - 1, whereas the other halogens have commons oxidation numbers of - 1, +1, +3, +5 and +7. The higher the oxidations state, the stronger the oxidizing ability.
For Example:
Chlorine in ClO2- ion has +3 oxidation state, whereas chlorine in ClO4- ion have +7 oxidation state. It means, ClO4- ion have the stronger oxidizing ability that ClO2- ion.
Halogen elements with positive oxidation numbers have a stronger oxidizing power in acidic solutions than in basic solutions.
From fluorine to iodine, the atomic radii of the halogen elements gets larger, as the atomic number increases. This is due to the increasing amount of atomic shell.
Electronegativity
Halogen elements have the greatest electronegativity value compared to other elements in the periodic table. From top to bottom, the electronegativity value of the halogen elements is getting smaller. Fluor is the element with the greatest electronegativity value among all elements in the periodic table.
Reactivity
Halogen is the most reactive non-metallic element. The reactivity of the halogen is due to its enormous electronegativity. The greater the electronegativity then the halogens will be more reactive. This is because the atom will more easily capture the electrons if the value of its electronegativity is high.
The reactivity of halogen elements decreases from fluor to iodine as the decreasing of electronegativity. Since the halogen element is highly reactive, in nature we can not find it in a free state. In nature, halogens are found in diatomic molecules
State In Standard Conditions (STP)
Iodine is a black solid. The iodine solid looks like a metal solid. But even so, chemically iodine shows the properties of nonmetallic elements.
The vapor pressure of bromine and iodine is quite high. Both of these compounds are usually stored in a sealed container. At the top of the bromine liquid, there will be a red-brown toxic vapor. Whereas if the iodine solid is heated gently, it will produce violet-colored toxic vapors.
Astatine is a radioactive halogen. All the astatine isotopes have a very short half-life. This makes it very difficult for a chemist to study its properties. The astatine isotope is highly unstable and releases radiation with high intensity.
However, the chemical properties of astatine follow the pattern shown by other halogen elements.
Another thing that makes chemists difficult to study this element is because astatine is the rarest element on earth. The entire crust of the earth as deep as 1 km is thought to contain only 44 mg of astatine.
Melting and Boiling Points
In nature, halogens are found in diatomic molecules. From fluorine to iodine, the melting and boiling point of the elements increases slowly. The melting and boiling points of halogens are depended on the ability of the molecule to polarize (polarizability).
Oxidation State
The oxidations state of fluorine is always - 1, whereas the other halogens have commons oxidation numbers of - 1, +1, +3, +5 and +7. The higher the oxidations state, the stronger the oxidizing ability.
For Example:
Chlorine in ClO2- ion has +3 oxidation state, whereas chlorine in ClO4- ion have +7 oxidation state. It means, ClO4- ion have the stronger oxidizing ability that ClO2- ion.
Halogen elements with positive oxidation numbers have a stronger oxidizing power in acidic solutions than in basic solutions.
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