Where Is the Halogen Family on the Periodic Table?
Learning Objective
- Describe the physical and chemical backdrop of halogens.
Key Points
- Halogens are nonmetals in group 17 (or VII) of the periodic tabular array. Downwardly the group, cantlet size increases. Equally a diatomic molecule, fluorine has the weakest bond due to repulsion between electrons of the modest atoms.
- Due to increased strength of Van der Waals forces downwardly the group, the boiling points of halogens increase. Therefore, the physical land of the elements down the group changes from gaseous fluorine to solid iodine.
- Due to their high constructive nuclear charge, halogens are highly electronegative. Therefore, they are highly reactive and can proceeds an electron through reaction with other elements. Halogens can exist harmful or lethal to biological organisms in sufficient quantities.
Terms
- halogensGroup 17 (or VII) in the periodic tabular array consisting of fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). They share similar chemic properties.
- electronegativityThe tendency of an cantlet to attract electrons to itself.
The halogens are a series of non-metal elements from grouping 17 of the periodic table (formerly Vii). The halogens include fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). The artificially created chemical element 117 (ununseptium) may also exist considered a element of group vii.
Physical Properties
Atoms get bigger downward the group as additional electron shells are filled. When fluorine exists as a diatomic molecule, the F–F bail is unexpectedly weak. This is considering fluorine atoms are the smallest of the halogens—the atoms are bonded close together, which leads to repulsion between costless electrons in the two fluorine atoms.
The boiling points of halogens increase down the grouping due to the increasing forcefulness of Van der Waals forces every bit the size and relative atomic mass of the atoms increase. This change manifests itself in a modify in the phase of the elements from gas (F2, Cltwo) to liquid (Br2), to solid (I2). The halogens are the merely periodic tabular array group containing elements in all 3 familiar states of matter (solid, liquid, and gas) at standard temperature and force per unit area.
Chemical Properties
Electronegativity is the power of an atom to concenter electrons or electron density towards itself within a covalent bail. Electronegativity depends upon the allure between the nucleus and bonding electrons in the outer shell. This, in turn, depends on the balance between the number of protons in the nucleus, the distance between the nucleus and bonding electrons, and the shielding effect of inner electrons. In hydrogen halides (HX, where 10 is the halogen), the H-10 bail gets longer as the halogen atoms get larger. This means the shared electrons are farther from the halogen nucleus, which increases the shielding of inner electrons. This means electronegativity decreases down the group.
Halogens are highly reactive, and they can exist harmful or lethal to biological organisms in sufficient quantities. This reactivity is due to loftier electronegativity and loftier effective nuclear charge. Halogens can gain an electron past reacting with atoms of other elements.
Fluorine is ane of the most reactive elements. Information technology reacts with otherwise inert materials such as glass, and information technology forms compounds with the heavier noble gases. Information technology is a corrosive and highly toxic gas. Fluorine'due south reactivity means that once it does react with something, it bonds and so strongly that the resulting molecule is inert and non-reactive. Fluorine can react with glass in the presence of pocket-sized amounts of water to form silicon tetrafluoride (SiF4). Thus fluorine must be handled with substances like the inert organofluorine compound Teflon.
Fluorine reacts vigorously with water to produce oxygen (O2) and hydrogen fluoride:
[latex]2 F_2 (g) + two H_2O (l) \rightarrow O_2 (g) + 4 HF (aq)[/latex]
Chlorine has maximum solubility of 7.ane chiliad per kg of h2o at ambience temperature (21 °C). Dissolved chlorine reacts to form muriatic acid (HCl) and hypochlorous acid (HClO), a solution that can be used equally a disinfectant or bleach:
[latex]Cl_2 (g) + H_2O (50) \rightarrow HCl (aq) + HClO (aq)[/latex]
Bromine has a solubility of 3.41 thou per 100 g of water. Information technology slowly reacts to course hydrogen bromide (HBr) and hypobromous acid (HBrO):
[latex]Br_2 (g) + H_2O (fifty) \rightarrow HBr (aq) + HBrO (aq)[/latex]
Iodine is minimally soluble in h2o, with a solubility of 0.03 g per 100 k water. However, iodine will form an aqueous solution in the presence of iodide ion. This occurs with the addition of potassium iodide (KI), forming a triiodide ion.
Source: https://courses.lumenlearning.com/introchem/chapter/properties-of-the-halogens/
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