Group 17 elements form
Group 17 elements, also known as the halogens, form when atoms of these elements combine in chemical reactions. The group 17 elements include fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). These elements are highly reactive nonmetals and tend to form 1- ions by gaining one electron to achieve a full outer electron shell. For example, chlorine (Cl) can react with sodium (Na) to form sodium chloride (NaCl) by gaining one electron from sodium. Similarly, bromine (Br) can react with potassium (K) to form potassium bromide (KBr) by gaining one electron from potassium. The reactivity of the halogens decreases from fluorine to iodine as you move down the group due to the increasing atomic radius and shielding effect. Astatine (At), the heaviest halogen, is radioactive and exists as a rare and unstable element.
Group 17 elements form the halogens. The halogens include fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). These elements are highly reactive nonmetals and are located in the second-to-last column (Group 17) of the periodic table. They have seven valence electrons, which allows them to readily gain one electron and achieve a stable octet configuration. Halogens have a wide range of chemical properties and are known for their high reactivity, ability to form compounds with alkali metals, and ability to form diatomic molecules (e.g., Cl2, Br2, I2). They are also often found in group 1A elements in nature and are important components of various compounds, such as common salt (NaCl) and chlorine bleach (NaClO).
Group 17 elements in the periodic table are known as halogens. The elements in this group are fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At). These elements exhibit similar chemical properties due to having the same number of valence electrons, which is seven.
To understand why these elements form a group, we need to look at their electronic configurations. Fluorine, for example, has an electron configuration of 1s2 2s2 2p5. If we analyze this configuration, we can see that fluorine has seven valence electrons in its outermost energy level.
Halogens are highly reactive elements because they have one less electron to reach a stable configuration like the noble gases (Group 18 elements) that have a full outer energy level. These halogens, therefore, tend to gain one electron from other elements to achieve stability by obtaining an electron configuration like the nearest noble gas.
For instance, when a chlorine atom gains one electron, it completes its outer energy level, becoming a negatively charged chlorine ion (Cl-). This electron configuration matches the electron arrangement of argon (1s2 2s2 2p6 3s2 3p6). Similarly, fluorine gains one electron to form fluoride (F-), bromine forms bromide (Br-), iodine forms iodide (I-), and astatine forms astatide (At-).
In summary, halogens in Group 17 form because they share similar properties, including having seven valence electrons and a tendency to gain one electron to achieve a stable electron configuration like the nearest noble gas.