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Halogens. Tusar Mollah Haley Mangiaruga, Amanda Perry. Properties of the Atom. Group 17- fluorine, chlorine, bromine, iodine, astatine Familiar states of matter =standard temperature and pressure Highly reactive Found in the environment only in compounds or as ions
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Halogens Tusar Mollah Haley Mangiaruga, Amanda Perry
Properties of the Atom • Group 17- fluorine, chlorine, bromine, iodine, astatine • Familiar states of matter =standard temperature and pressure • Highly reactive • Found in the environment only in compounds or as ions • Found in minerals and seawater • In natural products and living organisms • At room temperature is three different states of matter (solid, liquid and gas/vapor) • All elements in group 17 represent all 3 states of matter • Non-metallic elements • When moving down the group it decreases in electronegativity and reactivity, and increasing melting and boiling point
History and Discovery • 1842, Swedish chemist Baron Jӧn Jakob Berzelius proposed the term halogen which contains the four elements that produce a sea-salt-like substance when they form a compound with a metal
Chemical Properties and Reactions • Highly reactive • High effective nuclear charge • gain an electron by reacting with atoms of other elements • Fluorine is a corrosive and highly toxic gas • more reactive halogen can displace a less reactive halogen • reactivity of halogens decreases down Group 7 with increase in atomic number • The halogen atoms are only one electron short of pseudo Noble Gas electron arrangement, which are particularly stable. Therefore, in a chemical reaction, halogens try to complete the outer octet of electrons by forming a single covalent bond (sharing a pair of electrons)
Reasons for the similarities at the atomic level • Highly reactive due to the atoms being highly electronegative due to their high effective nuclear charge • 7 outer electrons • form singly charged negative ions • Form ionic compounds with metals • form covalent compounds with non-metals and with themselves
Everyday Use sand Common Reactions • Fluorine can react with glass in the presence of small amounts of water to form silicon tetrafluoride. • Chlorine and bromine are used as disinfectants for drinking water, swimming pools, fresh wounds, spas, dishes, and surfaces. They kill bacteria and other potentially harmful microorganisms through a process known as sterilization. Their reactivity is also put to use in bleaching. Sodium hypochlorite, which is produced from chlorine, is the active ingredient of most fabric bleaches and chlorine-derived bleaches are used in the production of some paper products. • Chlorine also reacts with sodium to create sodium chloride, which is another name for table salt.
Physical Properties • All halogens have seven electrons in outer shell giving them an oxidation number of -1