Analysis on the Application of "Isoelectronics" Knowledge

of. The calculations in the nine chapters of arithmetic are arranged vertically. For the convenience of viewing pictures, we changed it to horizontal, such as ,. The counting numbers listed from left to right in each row of the figure respectively represent the coefficients and corresponding constant terms of the unknown number. Express the calculation diagram shown in the form of the equation system that we are familiar with now, that is = similarly, we can express the calculation diagram as (2007 Hebei) the ancient Chinese "hetu" grid Composition, each square has a different number of dot plots, and the sum of the three dot plots in each row, each column, and each diagonal are equal.

Given some point diagrams of the "River Diagram", please calculate the corresponding point diagram of the P grid as the answer: (C) (2007 Jingmen, Hubei) The ancient Chinese mathematician Zhao Shuang's "Pythagorean Circle Square Diagram" Four congruent right triangles and a small square in the middle make up a large square (as shown). If the area of ​​the large square is 13, the area of ​​the small square is 1. The lengths of the two right sides of the right triangle are analyzed: It is known that the difference between the area of ​​a large square and a small square is equal to the area of ​​four triangles, namely: 2a6 = 13-1 = 12, and a2 (2006 Xiamen) fold bamboo land: there is a bamboo 篼 one foot, the final fold land, go to the book Three feet (three feet between the bamboo tip and the root). Ask the person who folds the geometry, (that is, how much is the upright bamboo grate). Please write the method C and the step solution MC 55 (foot) to answer this poem, that is, there are 4.55 foot bamboo in the original place.

Shenzhen Guangming Middle School (518107) Sheng Ping "Knowledge of electronic body" is a hot topic in college entrance examinations in the past years, but students in normal learning are quite afraid of this knowledge point. Doing such questions often scores badly. "Related knowledge to talk about my personal views.

C and D are particles formed by the first three periodic elements. Their total number of electrons is equal. It is known that methyl ethyl propylene is a diatomic molecule or a negative divalent diatomic anion, and D is an atom.

The ionic compound composed of propylene and calcium ions reacts with water to produce a flammable gas. The chemical equation of the reaction is the schematic diagram. The structure of the oxide body of butyl is similar to the crystal structure.

Analysis: This question is about the inference of short-period metamorphic knowledge, which involves the application of electronic knowledge such as Guan. The brief analysis is as follows: "The ionic compound composed of propylene and calcium ions reacts with water to produce a flammable gas." It is easy to think of CaC2 + 2H20-Ca (OH) 2 + C2H2T (if it is CaH2, it is not consistent with the meaning of the title described later), so C is an ion. Then the number of electrons contained in the particles of A, B, C, and D is 14. Since "A, B, C is a diatomic molecule", the molecule can be set to Zlfl type, with A representing the number of atomic nuclear charges), discuss the indefinite equation and get 3 combinatorial theory Answer: When = 6, '= 8, the molecule is C0; when Z, = 7, ZB = 7, the molecule is; when = 14, Zfl = 0, the substance is Si. The combination of the meaning, "B is reduction "Agent", should be CO, it is commonly used to make iron and other medium active gold (3CO + Fe203 = 3C02 + 2Fe). "Ding is an atom", it should be Si, so the armor can only be a simple substance. Note: The crystal structure of Si02 is similar to the structure of diamond and crystal Gui, and the other answers are omitted.

She Xue reflected on this question for the "14 Electronics" test, breaking the "10 Electronics" and "18 Electronics" conventional question setting methods, very innovative, can test students' innovative thinking. Reflect on our usual teaching of peer-to-peer electronic knowledge, there are the following limitations: First, the teaching method is not selected properly, the enumeration method is used to find out the qualified particles, and the students are rarely taught "fishing" through mathematical reasoning; second, the knowledge is not deepened enough. The idea is not broad, for example, for 18 electron particles, organic molecules are rarely considered. The application of relevant electronic body knowledge is now organized as follows.

It is generally believed that molecules with the same number of atoms and total electrons have a similar structure. This phenomenon is called the isoelectric principle. These molecules are called isoelectronics. The principle of isoelectronics is an approximate method to judge the structure of matter.

It is known that> 1, B, C, /) are four different particles, and there is the following conversion relationship between them: structural formula of / 1, electronic sub-particles of Z), and write 4 ions that react with B in solution The equations are all molecules containing 18 electrons. Analyze the structural characteristics of hydrazine and methylamine, and write the application of the knowledge of the structure electrons of organic compounds with the same number of electrons to the inference of inorganic block diagrams. The idea of ​​Xuanquan is to grasp the characteristics of common "1 electric one son" and "18 electronic" substances: substances that can be combined with AT ~ substances with basic particles NH3, I S2- and F-etc., substances that can react with H + In particular, the structure of the ion equation of the middle reaction: H2S-NH2) and methylamine-NH2) are both 9 +9 type, so consider using another 9 electron particles to replace: substances with equal total electron number of NH2, then The structure is the same and the physical properties are similar. ”It is called the principle of isoelectronics. The corresponding object shields are called isoelectronic bodies (BN). N is a new inorganic synthetic material. It is isoelectric with each other. Industry Two kinds of high-lubricant, electrical materials and heat-resistant materials can be prepared on the above.

P- (BN) n hardness is particularly high, which is a good material for ultra-high heat-resistant ceramic materials, abrasives, and precision tools. Question: What kind of single shield is it equivalent to each other? Analysis: This question is tested in the form of an information question. The transfer and application of body knowledge. The analysis of â‘  is as follows; (BN) a has 2n atoms, and the total number of electrons is 5n + 7a = 12 (because the atomic number of B is 5, and the atomic number is 7), according to the principle of isoelectronics, the element For, and 2X = 12, then X = 6. The element is (C2) n, that is, (BN) and carbon element are equal to each other. â‘¡The topic describes in detail the ot- (BN), p- (BN) B physics The nature implies that their structure is related to their physical properties. We transferred the relevant knowledge of the two allotropes of graphite and diamond of carbon, and found that a- (BN) b is similar to graphite, so as long as we grasp the characteristics of this type of quantium and conduct targeted training, it will change Students are afraid of this kind of problem, thus raising the score rate is contrary to the difference between the light, dispersion and scattering of light. Anhui Province Sixian No. 1 Middle School (234300) Zhi students often encounter the dispersion of light during the learning process , The problem of light diffraction and light scattering, the three concepts are now analyzed and distinguished, so that students have a clear understanding of these three concepts. Let us look at the misunderstanding of these two problems.

In the morning, the sun rises from the east, and people see the sun is red because of it.

The wavelength of red light is long, the diffraction phenomenon is obvious, the refractive index of red light is small, and the propagation speed is large. Red light is more likely to cause people's vision. As shown in the glass container, after adding fresh water, add a few drops of milk to make it cloudy Solution, let the white light reflect through the plane milling and shoot into the glass jar through the small hole of the cardboard. At this time, when you look at the light, the water is orange-red. If you stand on the side of the jar, the water is light blue. This phenomenon is.

(A) Interference of light (B) Total reflection of light (C) Diffraction of light (D) Dispersion of light Answer: (D) When a small obstacle LT or small holes, slits and other objects are encountered in the broadcast line, the light deviates The phenomenon of the original linear propagation direction has been eliminated. When the size of obstacles or small holes can be compared with the wavelength of light or even smaller than the wavelength of light, a significant diffraction phenomenon occurs. The dispersion of light generally refers to the decomposition of multicolor light into monochromatic light Phenomenon, but in essence it means that when light passes through a substance, the speed of light propagation will be less than the speed in a vacuum, and it changes with frequency, thus showing that the same substance has different refractive indices for different frequencies of colored light. The phenomenon that colored light breaks down into monochromatic light.

Light scattering means that when light passes through a non-uniform medium, for example, when light passes through turbid substances such as dust, smoke, mist, suspension, emulsion, etc., the linearity of impurity particles due to these turbid substances is generally better than that of light. The wavelength is small, and the distance between them is larger than the wavelength, thereby forming scattered light. Carefully analyze the difference between the concepts of light diffraction, light dispersion, and light scattering. We will find that the answer to Example 1 confuses the two concepts of light diffraction and light scattering. Diffraction is formed by individual uneven regions (such as individual small holes, slits, or small obstacles, etc.). The size of these uneven regions is generally comparable to the wavelength of light; and the scattering of light is due to Older children are formed by a collection of irregular and non-uniform small "regions". The linearity of these non-uniform small "regions" is generally smaller than the wavelength. Although diffraction also occurs for each of these small "regions", due to the irregular arrangement, irrelevant superposition occurs with each other, so as a whole, no diffraction phenomenon is observed. This scattering phenomenon of particles whose linearity is smaller than the wavelength of light to human light is generally called Rayleigh scattering. This relationship of scattered light intensity inversely proportional to the fourth power of the wavelength is called Rayleigh's law. Rayleigh's law shows that short-waves dominate in scattered light, so when observing white light scattering, it has a blue color, and the light directly passes through the scattering material. , Because of the lack of short-wave components, it looks red. For example, the wavelength of red light (A = 7.2x107m) is 8 times that of purple light. According to Rayleigh ’s law, the intensity of purple light emitted by people is equal to the intensity of red light. 1 B is a reducing agent when it is high, please use chemical equations to express its important use in industry 2 Under certain conditions, the element symbol of the chemical equation D reacts with 02 is its atomic junction

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