BTC momentum

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3. The first chapter is about the atomic structure and periodic system of elements
2. Break the normal arrangement rules of elements in the three-dimensional world, let the contestants arrange elements electronically or redraw the periodic table of elements under new conditions or "rules", and speculate the valence and properties of elements
3. According to the relationship between several elements, their positions in the periodic table can be inferred
4. Apply the knowledge of chemistry, physics and other disciplines to investigate the latest scientific and technological achievements
trend prediction: the future chemical competition questions will emphasize the connection between chemistry and physics, and the application of atomic structure and periodic system knowledge in daily life. To test the contestants' creative thinking ability of breaking "old knowledge" and establishing "new knowledge". The author believes that: if we examine the above knowledge points, we will still make an article in the above aspects< The relative atomic mass (atomic weight) of an element is the ratio of one mole mass of an element to one mole mass of nuclide 12C. This definition shows that: (1) the relative atomic mass of an element is a pure number. ② The relative atomic mass of a single nuclide element is equal to that of its nuclide. ③ The relative atomic mass of a multi nuclide element is equal to the weighted average of the relative atomic mass of its natural isotopes< (1) Bohr planetary model of atomic structure (motion of extranuclear electrons)
1. Hydrogen atomic spectrum
Balmer found out in 1833 that the relationship between the wavelengths of all spectral lines in the visible region of hydrogen atomic spectrum is that B is a constant
in 1913, Rydberg summed up the general formula of the relationship between spectral lines ν= R (1 / n12-1 / N22), R is Rydberg constant, its value is 3.19 × 1015 cycles per second. The relationship between the above formula N1 and N2 corresponding to the spectral lines in each region is:
in the ultraviolet region: N1 = L, N2 = 2, 3, 4...
in the visible region: N1 = 2, N2 = 3, 4, 5...
in the infrared region: N1 = 3, N2 = 4, 5, 6...
2. Bohr's Theory (characteristics of the motion of the extranuclear electrons)
in 1913 Bohr's Planck quantum theory On the basis of Einstein's photonics theory and Rutherford's nuclear atom model, in order to clarify the results of hydrogen atomic spectrum experiment, three hypotheses of atomic structure theory, called Bohr theory, are put forward. The main points are as follows:
① the electrons outside the atomic nucleus do not move around the nucleus in any orbit, but the orbital angular momentum P must meet the following conditions:
P = NH / 2 π， N is a positive integer and H is the Planck constant. The orbit that meets the above conditions is called stable orbit, and the electrons moving on the stable orbit do not release energy< (2) the farther the electron orbit is from the nucleus, the higher the energy is. Usually the electron moves in the nearest orbit to the nucleus, when the energy of the atom is the lowest, which is called the ground state. When the atom gains energy from the outside, the electron can jump to the high energy orbit far away from the nucleus, which is called the excited state
③ the excited state is unstable, the electron will jump from the higher level to the lower level, and release the excess energy in the form of light< At the same time, Bohr also calculated and deced the energy formula according to the classical mechanics and quantization conditions:

Bohr theory has great limitations, it can only explain the atomic spectrum of hydrogen, can not explain the atomic spectrum of multi electron system, and even can not explain the fine structure of hydrogen spectrum. At the beginning of the 19th century, e to the experiments of light interference, diffraction and photoelectric effect, people knew the special law of microscopic particle motion wave particle ality. These two properties were quantitatively linked by Planck constant, e = H ν P＝h/ λ， So the essence of light is revealed. Where e is energy and P is momentum, λ Is the wavelength, h is the Planck constant. Later, electron diffraction experiments proved the wavelength of electrons λ= h/m υ， M is the mass of the electron, υ Is the velocity of the electron< (2) the quantum mechanical model of hydrogen atomic structure (motion state of extranuclear electrons)
(1) probability density and electron cloud
Ψ｜ 2 is the probability of electrons appearing in the unit volume element of extra nuclear space, which is called probability density. The proct of the probability density and the total volume of the region is the probability of electrons appearing in the region
electron cloud is a kind of image to describe the motion of electrons outside the nucleus, which is related to probability density Ψ｜ 2, it is based on the concept of statistics to visualize the probability density of extranuclear electrons. That is Ψ｜ 2< (2) the physical meaning of the four quantum numbers
a. the main quantum number n is the number of electron layers, the average distance from the electron to the nucleus and the energy level. The values are 1, 2, 3,..., 0 (positive integer)
B. the angular quantum number L, which determines the shape of the atomic orbit (or electron cloud), is 0, 1, 2,..., (n-l). For example, when l = 0, it is an s orbit with star shape distribution; When l = 1, it is a p-orbit with mbbell distribution; When l = 2, it is d-orbit and petal shaped. In the multi electron system, l is also related to energy, just as the energy of each sublayer orbit in a main layer is different, that is, ENS < ENP < end
C. the magnetic quantum number m determines the extension direction of the atomic orbit (or electron cloud) in space. The value is 0, ± 1， ± 2，…， ± L
for example, when l = 1, M can have three values, namely 0, + 1 and - 1, indicating that there are three different extension directions of P sublayer orbits, namely Px, py and PZ
D. the spin quantum number MS does not depend on N, l and m. It is not the result of solving Schrodinger equation, but the result of experimental measurement. It shows that electrons rotate clockwise or counterclockwise about their own axis. The values are + 1 / 2 or - 1 / 2 respectively< Third, the arrangement of extranuclear electrons, the periodic system of elements and the periodicity of elements. ② Pauli's incompatibility principle. ③ The hunt rule
2. Shielding effect in a multi electron atom, e to the repulsive effect of other electrons on an electron, a part of the nuclear charge is offset, resulting in the decrease of the effective nuclear charge and weakening the attraction of the nuclear charge to the electron, which is called shielding effect or shielding effect. Due to the shielding effect, the energy levels of different sublayer orbitals with the same principal quantum number are split. The penetration effect refers to the phenomenon that the outer electrons drill into the inner space and get close to the nucleus. The order of electron penetration effect in each sublayer is ns > NP > nd > NF. The deeper the electron penetrates, the less it is shielded by other electrons, the more attractive it is to the nucleus, and thus the lower its energy. Therefore, the order of orbital energy of each sublayer with the same N and different L is ENS < ENP < end < enf. When n and L are different, the energy levels are staggered, that is e4s < E3D. This phenomenon is related to the penetration effect of electrons. Because the penetration ability of 4S is stronger than that of 3D, although the maximum peak of 4S is far away from the nucleus than that of 3D, because it has a small peak which drills very close to the nucleus, it has a great influence on recing the orbital energy, resulting in e4s < E3D< The relationship between the atomic structure and the position of an element in the periodic table is discussed. A group of energy levels is equivalent to a period, which can be divided into long and short periods. Short period (there are only s and P levels in the energy level group). Long period (in addition to s and P levels, there are also D and F levels in the energy level group)
2. The elements with the same valence electron structure have the same family number. There are two kinds of Clans: Main clans and sub clans. The main group is usually called a group and the sub group is called B group
group a element: its group number is equal to the number of electrons in NS and NP layers, such as 3s23p4, which is the Group VI a element of the third period
group B elements: A. when the total number of electrons on the (n-1) DNS layer is 3 ~ 7, the number of electrons is the group B number of the element. For example, 5d56s2 is the element of group Ⅶ B in the sixth period
B. when the total number of electrons in (n-1) DNS layer is 8 ~ 10, they are all group VIII elements, such as 3d84s2, which is the Group VIII element in the fourth period
C. when (n-1) d10ns, the total number of electrons on the NS layer is the number of group B. For example, 4d105s2 is the group II element of the fifth cycle< (3) the grouping of elements in the periodic table

5. The periodic relationship between the atomic structure and the properties of elements
1. The variation of atomic radius in the periodic table: from top to bottom in the same main group, the atomic radius increases with the increase of the number of electron layers. Although the increase of nuclear charge from top to bottom tends to rece the atomic radius, it is not the main factor. The change of group B elements is not obvious, especially for the elements of the fifth and sixth cycle, because of the shrinkage of lanthanide, the radii are very similar. In the same period, for the short period, with the increase of the nuclear charge number from left to right, the attraction of the nucleus to the outer electrons increases correspondingly, and the atomic radius decreases graally. For the long period, as the number of nuclear charges increases, the newly added electrons fill the (n-1) d orbital. For the outermost electron layer which determines the size of atomic radius, the shielding effect of electrons on the secondary outer layer is much greater than that between the outermost electrons. Therefore, most of the increased nuclear charges from left to right are shielded by the increased (n-1) d electrons, that is, the effective nuclear charges increase slowly, so the atomic radius decreases little from left to right. When the electron layer structure is (n-1) D10, the atomic radius increases slightly e to the larger shielding effect on the outer electrons. When the electron layer structure is (n-2) F7 and (n-2) F14, the atomic radius increases slightly, and the atomic radius of noble gas increases suddenly at the end of each cycle The radius of noble gas is van der Waals radius
② the ionization potential and electron affinity of electronegative elements only reflect the ability of atoms to gain and lose electrons from one aspect, but in fact they have some limitations. When atoms combine with each other, the difficulty of losing electrons and getting electrons must be considered together. The ability of an atom to attract electrons in a molecule is usually called the electronegativity of an element. According to the electronegativity of elements, the strength of metallic and non-metallic elements can be measured. The electronegativity of elements also shows a periodic change, the general trend of change: the same period increases from left to right, the same family decreases from top to bottom. Therefore, according to the periodic table, the electronegativity of fluorine in the upper right is the highest, that is, the non-metallic element is the strongest, and the electronegativity of cesium in the lower left is the lowest, that is, the gold attribute is the strongest< (4) using s, P, D to represent the ground state configuration (including neutral atoms, positive ions and negative ions)

Chapter 2 molecular structure

competition point inction: the judgment of molecular structure is the most basic knowledge of chemistry, and also the knowledge point of chemical competition examination. In recent years, the knowledge points often appear in the chemical competition when examining the molecular structure are as follows:
1. According to the hybrid orbital theory, the hybrid state of the central atom can be judged
2. Judging the shape of molecules according to Lewis electron theory
3. The shape of the molecule can be judged according to the valence layer electron pair repulsion theory
4. The structure of unknown molecules can be determined according to the isoelectronic principle
of course, there are many forms of examination, and the form of examination is not single

4.

One hundred million won may not have any concept for us. We should convert it into RMB first

according to the bank exchange rate, the median price of 100 won against RMB is 0.6203, and that 100 million won is 622329.8161 yuan

in China, more than 600000 people are not rich, but they are not poor

in South Korea, this needs to be based on the income to expenditure ratio of South Korea. If the annual salary is 100 million won, it should not be considered a poor person; But if all assets are only 100 million won, it should be considered half a poor person

5. 大叶兰冠号SO,
OU,OW,
FN,FM,FL,FO,
KG,KF,KE,
CL,CK,
DN,DO,
ZM,
WK,
首发冠号FA
补冠号AD,AE,AG,AH,AI,AJ
UA,UB,UC,UD,UE,UF,UO
HS,HT,HU,HW,HX.HY.HZ
XT,XS,XU,XW,XX,XY,XZ
YK,YL,YO,YM,YN,
MS,MU,MY,MZ,ME,MF,MG,MH,MI,MJ
JK,JM,JO
OL,OM,ON,OO
数字冠OI,OO,II,OI