A. Compare The Elemental Properties
If you look again the periodic table there are
hundreds of elements. Each has different characteristics and characteristics.
The chemists classify these elements into two major groups namely the elements
of metal and non-metallic elements with the following properties.
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Metal Elements
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Non-Metallic Element
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Beings on except mercury
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Liquid, solid, or gas
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Physically strong and can be forged
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Physically fragile and unforgivable
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Easy to conduct electricity and heat
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It is difficult to conduct electricity and heat
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B. Properties of Compounds
If there are two or more chemical elements joined
will form a compound. Compounds of the formation of these elements are
completely different from the constituent elements. For example, the H2O water
body is liquid and jearnih. Though the water tastes from the element of
hydrogen and noxigen which are both colorless gas and can not be seen with
normal vision.
C. The nature of the mixture
A mixture may be a combination of elements with
other elements or elements with the compound. Examples of stainless steel or
often we are familiar with the term stainless steel is a mixture of iron,
nickel, and chrome.
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Elements
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Compound
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Mixed
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Composed of one type of atom
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It is composed of two or more atoms through a
chemical reaction
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Composed of two or more atoms through physics
events
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Can not be broken down into smaller substances through ordinary chemical
reactions
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Can be reduced to its constituent elements through
ordinary chemical reactions
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Can be separated into constituent elements through
physics events
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The mass composition of the constituent elements
is always fixed
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The
mass comparisons of the constituent elements are not always fixed
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Its nature is very different from the nature of
its constituent elements
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It has properties of its constituent properties.
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The fourth period transition elements can form a colored compound except zinc. Why zinc compound is colorless?
BalasHapusSorry, to my knowledge zink has flame color Zink burns in air with bright blue bluish green, then frees zinc oxide smoke.
HapusExplain the characteristics of the halogen element
BalasHapusCharacteristics and Properties of Halogen Elements
HapusFluorine
Found in fluorspar by Schwandhard in 1670 and only in 1886 Maisson succeeded in isolating it. It is the most electronegative and most reactive element. In the form of gas is a diatom molecule (F2), it smells spicy, is yellow and very mildly corrosive. Metal powder, glass, ceramics, even water burns in fluorine with bright flame. The presence of a fluorine component in drinking water exceeds 2 ppm can cause a black layer of teeth
Chlorine
Discovered by Scheele in 1774 and named by Davy in 1810. Chlorine is found in nature in a combination state as Cl2 gas, compounds and minerals such as kamalite and silvit. Chlorine gas is greenish yellow, water soluble, easy to react with other elements. Chlorine can interfere with breathing, damage the membrane lenders and in the form of light can burn the skin.
Bromine
Discovered by Balard in 1826. is a reddish-brown, slightly volatile liquid at room temperature, its vapor is red, smells bad and can cause irritating effects on the eyes and throat. Bromine is readily soluble in water and CS2 forms a red solution, less active than chlorine but more reactive than iodine.
Iodine
Discovered by Courtois in 1811. It is a non-metallic element. Glossy blackish-colored solids. Can evaporate at ordinary temperatures to form purple-blue gas that smells bad (stinging). In nature found in salt water (salt water) chili, etc. These halogen elements dissolve well in CHCl3, CCl4, and CS2 but are very little soluble in water. There are known to be 23 isotopes and only one stable is 127I found in nature. Iodine crystals can injure the skin, while the steam can injure the eyes and mucous membranes.
Astatin
It is the first radioactive element created as a result of the Bismuth bombardment with alpha particles (synthesized in 1940) by DR. Corson, K.R. Mackenzie and E. Segre. There are known 20 isotopes of astatin, and the isotope At (210) has a half-life of 8.3 hours (the longest). Astatin is more metal than iodine. Its chemical properties are like iodine, can form intermediate halogen compounds (AtI, AtBr, AtCl), but it is not yet known whether At can form diatom molecules like other halogen elements. Compounds that were successfully detected were HAt and CH3At (Raharjo, 2010)
Properties of Halogen Elements
Physical properties of halogen elements
Flourin and chlorine are gas at room temperature because boiling point and melting / freezing point is lower than room temperature (25oC).
Bromine has a boiling point higher than the room temperature, while the melting point is lower so that the liquid form.
Iodine is solid as its boiling point and freezing point are higher.
The solubility of halogens in water in one class from top to bottom solubility decreases as the relative atomic mass increases. However, fluorine does not dissolve but reacts:
Hapus2F2 + 2H2O → 4HF + O2
While bromine solubility is greatest because of the liquid tangible (most soluble). Iodine is difficult to dissolve in water. In order for iodine to dissolve well, added KI salt. Reaction:
I2 + KI → KI
Chemical properties of halogen elements
The radius of the atom from top to bottom in the periodic table is increasing as the number of skin is filled with more electrons.
The radius of an ion is larger than the atomic radius because it will receive electrons so that its skin is fully charged.
The electronegativity of F to I is smaller because the fingers are so large that they will lie far from the nucleus, the electrons will be difficult to accept.
The ionization energy from top to bottom gets smaller because if the radius of a small atom, closer to the nucleus, the ionisation energy gets stronger.
The sequence of properties of the halogen reactivity can be seen from the following reactions:
Potential reduction data:
F2 + 2e- → 2F- Eo = +2,87 Volt
Cl2 + 2e- → 2Cl- Eo = +1,36 Volt
Br2 + 2e- → 2Br- Eo = +1,06 Volt
I2 + 2e- → 2I- Eo = +0.54 Volt
F2 reduction potential is greatest so it will be easy to experience reduction and is called the strongest oxidizer. While the weakest is I2 because it has the smallest reduction potential.
Oxidizing properties: F2> Cl2> Br2> I2
Reductor properties: I-> Br-> Cl-> F-
The strongest reducer will easily oxidize easily release electrons Iodide ion most easily remove electrons so that it acts as a powerful reductor (Anonymous, 2010).
You try to explain what is the Metal Element, Non Metal Element and Semi Metal Elements?
BalasHapusKnown elements exist in the form of metals, not metals (non-metals), and semilogam.
Hapus1. Metal Elements
Metals are elements that have shiny properties and are generally good conductor of electricity and heat conductor. Metal elements are generally solid at normal temperatures and pressures, except mercury in the form of liquid. In general, metal elements can be forged so that can be formed into other objects.
2. Non Metal Elements
The non-metallic element is an element which has no metallic properties. In general, non-metallic elements are gaseous and solid at normal temperature and pressure. Examples of non-metallic elements in the form of gases are oxygen, nitrogen, and helium. Examples of non-metallic elements in solid form are sulfur, carbon, phosphorus, and iodine. Non-metallic solids are usually hard and brittle.
3. Semi Metal Elements
In addition to metal and nonmetal elements there is also a semilogam element or known as a metaloid. Metaloid is an element that has metallic and nonmetal properties. Semilogam element is usually semiconductor. What is a semiconductor? Semiconductor materials can not conduct electricity well at low temperatures, but their electrical conductivity becomes better when the temperature is higher.