Before we delve into the details of these important elements, let's get some terminology straight. The tendency to form multiple bonds and to catenate decreases as the atomic number increases. You'll find more specific groups, like transition metals, , alkali metals, alkaline earth, halogens, and noble gasses. Only polonium is metallic, forming either the hydrated Po 2+ or Po 4+ ion in aqueous solution, depending on conditions. Although germanium is indeed one of the rarer elements, it assumed importance upon recognition of its properties as a semiconductor i.
It has 27 isotopes, 9 stable and 18 unstable. Diamonds are much different from graphite and amorphous carbon. Without cross-linking, silicones are waxes or oils, but cross-linking can produce flexible materials used in sealants, gaskets, car polishes, lubricants, and even elastic materials, such as the plastic substance known as Silly Putty. These isotopes are lead-209, lead-210, lead-211, and lead-212. Although she was never able to obtain macroscopic quantities of the element, which she named for her native country of Poland, she demonstrated that its chemistry required it to be assigned to group 16. Also a certain amount of chemistry of the chlorides and oxides.
In order to keep the words cation and anion straight, I always think of a cute cat for cation, which is positive, just like a cation's charge. This oxidation state means that no electrons were lost and four were gained from another element. Because oxygen is so electronegative, the O—H bond is highly polar, creating a large bond dipole moment that makes hydrogen bonding much more important for compounds of oxygen than for similar compounds of the other chalcogens. Graphene, a single carbon sheet with intriguing electronic properties, is the basis for these allotropes. He had invested money in a sulfuric acid plant and decided to investigate a foul-smelling contaminant that formed a red precipitate. They are sliced into very thin wafers that are highly polished and then cut into smaller pieces for use as chips.
Sulfur is also recovered from H 2S and organosulfur compounds in crude oil and coal and from metal sulfide ores such as pyrite FeS 2. Germanium ore concentrates are mostly sulfidic, e. The used the metal as plates on which to record inscriptions. When rapidly melted, it forms the black, vitreous form, which is usually sold industrially as beads. Note the Pattern Just as with the other groups, the tendency to catenate, the strength of single bonds, and reactivity decrease down the group. Molecular orbital diagram for the formation of O 2.
They are far outside the scope of General Chemistry. The term polysulfide often refers to a class of polymers with alternating chains of several sulfur atoms and hydrocarbon substituents. Lead forms four oxides, a sulfide, a selenide, and a telluride. Lead Lead, also known as plumbate , is similar to tin in that it is a soft, malleable metal with a low melting point. Because the strength of the Y—H bond decreases with increasing atomic radius, the stability of the binary hydrides decreases rapidly down the group.
Exercise Predict the products of the reactions and write a balanced chemical equation for each reaction. Winkler realized that the sample was 75% silver, 18% sulfur, and 7% of an undiscovered element. None of these are naturally occurring. Germanium forms tetrahalides with all halogens except astatine and forms dihalides with all halogens except bromine and astatine. The carbon group elements Group 14 , with four electrons, occupy a middle position. The ores are mixed with coke and and to produce pure lead.
Organic tin compounds, such as and are highly toxic, and can disrupt metabolic processes inside cells. It may have functioned as a catalyst in the formation of the earliest organic molecules Sadava 62. Metallic and non-metallic character: As we go down the group the atomic number increases and it changes from nonmetals to metals. Tin and lead are soft metals that are too weak for structural applications, but because tin is flexible, corrosion resistant, and nontoxic, it is used as a coating in food packaging. Compounds of silicon, germanium, tin, and lead with the same stoichiometry as those of carbon, however, tend to have different structures and properties.
Carbon's atomic radius is 77 , silicon's is 118 picometers, germanium's is 123 picometers, tin's is 141 picometers, and lead's is 175 picometers. The last member of the group 14 elements to be discovered was germanium, which was found in 1886 in a newly discovered silver-colored ore by the German chemist Clemens Winkler, who named the element in honor of his native country. Some of these allotropes are formed in the decomposition of graphite. Pb is the chemical symbol of lead. It is available in both free and a combined state. The orthorhombic form Sα is more stable up to 95 °C, while the β-form is the thermodynamic form.