The octaelectron outer sheath has an ion.
Lorentz's force call the power that acts from the part magnetic field on a moving electric charge. Very often, the force of Lorentz is called only the magnetic component of this field. Formula for determination:
F \u003d Q (E + VB),
where q. - particle charge;E. - electric field strength;B. - magnetic field induction;v. - particle speed.
Lorentz's power is very similar in its principle on, the difference is that the latter acts on the entire conductor, which is generally electrically neutral, and lorentz's power describes influence electromagnetic field Only on a single moving charge.
It is characterized by the fact that it does not change the speed of movement of charges, but only acts on the velocity vector, that is, it is capable of changing the direction of movement of charged particles.
In nature, Lorentz power allows to protect the Earth from exposure to cosmic radiation. Under its influence, the charged particles falling on the planet are deviated from the direct trajectory through the presence of the magnetic field of the Earth, causing polar beams.
In the technique, Lorentz power is used very often: in all engines and generators it is she leads to rotation rotor Under the action of the electromagnetic field of the stator.
Thus, in any electric motors and electric drives, Lorentseva is the main type of force. In addition, it is used in accelerators of charged particles, as well as in electronic guns, which were previously installed in the lamp televisions. In the kinescope, the electrons emitted by the cannon deflect under the influence of the electromagnetic field, which happens with the participation of the Lorentz force.
In addition, this force is used in mass spectrometry and mass electron for instruments capable of sorting charged particles depending on their specific charge (charge ratio to the mass of the particle). This allows high accuracy to determine the mass of particles. Also finds use in other instrumentation, for example, in a non-contact method for measuring the consumption of electrically conductive liquid media (flow meters). This is very relevant if the liquid medium has a very high temperature (melt of metals, glass, etc.).
The structure of electronic shells of atoms of elements of the first four periods:s. - andp. - andd. - elements. Electronic atom configuration. The main and excited state of atoms
1. The number of electrons in the atom is determined
the number of protons
number of neutrons
the number of energy levels
the value of the relative atomic mass
2. Ion, consisting of 16 protons and 18 electrons, has a charge
1) +4 2) -2 3) +2 4) -4
4. Configuration of the outer electronic layer of the sulfur atom in an unexcited state
1) 4S 2 2) 3 S 2 3P 6 3) 3S 2 3P 4 4) 4S 2 4P 4
5. Electronic configuration 1S 2 2S 2 2P 6 3S 2 3P 6 4S 1 is basically the state has an atom
1) lithium 2) sodium 3) potassium 4) calcium
6. The eight-electronic outer sheath has an ion
1) P 3+ 2) S 2-3) C1 5+ 4) Fe 2+
7. The two-electron outer sheath has ion
1) S 6+ 2) S 2-3) BG 5+ 4) SN 4+
8. The number of electrons in Iron FE 2+ is equal to
1) 542) 283) 584) 24
9. Electronic configuration IS. 2 2 s. 2 2 p. 6 3 s. 2 3 p. 6 corresponds to ion
1) SN 2+ 2) S 2-3) CR 3+ 4) Fe 2+
10. In the main state, three unpaired electrons has an atom
1) silicon 2) phosphorus 3) sulfur 4) chlorine
11. Element with electronic external configuration ... 3 s. 2 3 p. 3 Forms hydrogen connection Composition
1) EN 4 2) EN3) EN 3 4) EN 2
12. Electronic configuration IS 2 2S 2 2P 6 3S 2 3P 6 corresponds to ion
1) CL - 2) N 3-3) BR - 4) O 2-
13. Electronic configuration IS. 2 2 s. 2 2 p. 6 corresponds to ion
1) A1 3+ 2) Fe 3+ 3) Zn 2+ 4) CR 3+
14. The same electronic configuration external levels have CA 2+ and
1) K + 2) Ar 3) VA4) F -
15. Metal atom, the highest oxide of which IU 2 O 3, has electronic formula External energy level
1) nS. 2 etc 1 2) nS. 2 etc 2 3)nS. 2 nP. 3 4)nS. 2 nP. s.
16. The element to which corresponds higherthe composition of R 2 O 7 has an electronic external configuration:
1) nS. 2 nP. 3 2)nS. 2 nP. 5 3)nS. 2 nP. 1 4)nS. 2 nP. 2
17. Higher oxide compositionR. 2 O. 7 Forms a chemical element, in the atom of which the electron levels filling with electrons corresponds to rownumbers:
1) 2, 8, 12) 2, 8, 73) 2, 8, 8, 14) 2, 5
18. At the sulfur atom, the number of electrons in the external energy level and the nucleus charge is equal, respectively
1) 4 and + 16 2) 6 and + 32 3) 6 and + 16 4) 4 and + 32
19. The number of valence electrons in manganese is equal
1)1 2) 3 3) 5 4) 7
20. The same electron structure has particles
1) Na 0 and Na + 2) Na 0 and k 0 3) Na + and F - 4) CR 2+ and CR 3+
21. Higher oxide composition EO 3 forms an element with an electronic configurationc. out of an external electronic layer
1) nS. 2 nP. 1 2) nS. 2 nP. 3 3) nS. 2 nP. 4 4) nS. 2 nP. 6
22. The number of energy layers and the number of electrons in the external energy layer of arsenic atoms are equal, respectively
1)4 , 6
2, 5
3, 7
4, 5
23 Al 3+ ionics meets the electronic configuration:
1) 1s. 2 2s. 2 2p. 6 ; 2) 1s. 2 2s. 2 2p. 6 3s. 1 ; 3) 1s. 2 2s. 2 2p. 6 3s. 2 3P. 1 4) IS. 2 2s. 2 2p. 6 3s. 2 3P. 6 4S. 1
24. ionzn. 2+ ResponsibleElectronic Configuration:
1) 1S 2 2S 2 2P 6 3S 2 3P 6 3D 8 4S 2 2) 1S 2 2S 2 2P 6 3S 2 3P 6 3D 10 4S 2 4P 6 3) 1S 2 2S 2 2P 6 3S 2 3P 6 3D 10 4) IS 2 2S 2 2P 6 3S 2 3P 6 4S 1
25. Chemical element corresponds to a volatile hydrogen compound of the composition Rh 3. Electronic configuration of the external level of this element
2 3 p. 13s. 2 3 p. 2
3s. 2 3 p. 3
3s. 2 3 p. 5
26. Sulfur and oxygen atoms have
27. Electronic configuration of the fluorine atom
2 2s. 2 2p. 51s. 2 2s. 2 2p. 4
1s. 2 2s. 2 2p. 6
1s. 2 2s. 2 2p. 3
Answers : 1-1, 2-2, 4-3,5-3,6-2,7-3,8-4,9-2, 10-2, 11-3, 12-1, 13-1, 14-1, 15-1, 16-2, 17-2, 18-3, 19-4, 20-3, 21-3, 22-4, 23-1, 24-3, 25-4, 26-2, 27-1
1. Eight electronic outer sheath has ion
1) P 3+ 2) S 2-3) C1 5+ 4) Fe 2+
2. The two-electron outer sheath has ion
1) S 6+ 2) S 2-3) BG 5+ 4) SN 4+
3. Number of electrons in iron ionFe 2+ is equal
1) 54 2) 28 3) 58 4) 24
4. Electronic configurationIS.2 2 s.2 2 p.6 3 s.2 3 p.6 corresponds to ion
1) SN 2+ 2) S 2-3) CR 3+ 4) Fe 2
5. In the main state, three unpaired electron has an atom
1) Silicon
2) Phosphora
3) sulfur
4) Chlora
6. Element with electronic external configuration ... 3 s.2 3 p.3 forms a hydrogen compound
1) EN 4 2) EN 3) EN 3 4) EN 2
7. Electronic configurationIS 2 2 S 2 2 P 6 3 S 2 3 P 6 corresponds to ion
1) with L - 2) N 3-3) BR - 4) O 2-
8. Electronic configurationIS.2 2 s.2 2 p.6 corresponds to ion
1) A1 3+ 2) Fe 3+ 3) Zn 2+ 4) CR 3+
9. The same email configuration has sa2+ I.
1) K + 2) A R 3) BA 4) F -
10. Metal atom, the highest oxide of which2 O 3. has an electronic formula of an external energy level
1) nS.2 etc1 2) nS.2 etc2 3) nS.2 nP.3 4) nS.2 nP.s.
11. The element to which corresponds higheroxide compositionR 2 O 7 Has an electronic external configuration:
1) nS.2 nP.3 2) nS.2 nP.5 3) nS.2 nP.1 4) nS.2 nP.2
12. Higher oxide composition R.2 O.7 forms a chemical element, in the atom of which the electron levels filling with electrons corresponds to rownumbers:
1) 2, 8, 1 2) 2, 8, 7 3) 2, 8, 8, 1 4) 2, 5
13. The greatest radius has an atom
1) tin 2) silicon 3) lead 4) carbon
14. In a number of chemical elements
Na -\u003e Mg -\u003e Al -\u003e Si
1) the number of valence electrons in atoms increases
2) the number of electronic layers and atoms decreases
3) the number of protons in atomic nuclei decreases
4) radius of atoms increase
15.Tell radius has an atom
1) bromine 2) arsenic 3) barium 4) tin
16.Electronic configuration 1.s 2 2 S 2 2P 6 3. S 2 VR 6 3 D 1 has ion
1) Ca 2+ 2) A1 3+ 3) k + 4) SC2+
17. At the sulfur atom, the number of electrons in the external energy level and the nucleus charge is equal, respectively
1) 4 and + 16 2) 6 and + 32 3) 6 and + 16 4) 4 and + 32
18. The number of valence electrons in manganese is equal
1) 1 2) 3 3) 5 4) 7
19. The same electronic structure has particles
1) Na 0 and Na + 2) Na 0 and k 0 3) Na + and F - 4) CR 2+ and with R 3+
20. Higher oxide of EO composition3 forms an element with an electronic configurationc. out of an external electronic layer
1) NS 2 NP 1 2) NS 2 NP 3 3) NS 2 NP 4 4) NS 2 NP 6
21. The number of energy layers and the number of electrons in the external energy layer of arsenic atoms are equal, respectively
4 , 6 |
|
2, 5 |
|
3, 7 |
|
4, 5 |
22. What electronic configuration has an atom of the most active metal?
1s.22s.22p.1 |
|
1s.22s.22p.63s.1 |
|
1s.22s.2 |
|
1s.22s.22p.63s.23p.1 |
23. The number of electrons in the atom is determined
the number of protons |
|
number of neutrons |
|
the number of energy levels |
|
the value of the relative atomic mass |
24. The 81 BR atom core contains
1) 81 p and 35 n 2) 35 p and 46 n 3) 46 p and 81 N 4) 46 p and 35 n
25. ion, consisting of 16 protons and 18 electrons, has a charge
1) +4
2) -2
3) +2
4) -4
26. The external energy level of the atom of the element forming the highest oxide of the composition of the ESA has a formula
1) NS 2 NP 1 2) NS 2 N p 2 3) n s 2 n p 3 4) NS 2 N p 4
27. Configuration of the outer electronic layer of the sulfur atom in an unexcited state
1) 4 s 2 2) 3 s 2 3r 6 3) 3 s 2 3r 4 4) 4 s 2 4p4
28. Electronic configurationIS 2 2 S 2 2 P 6 3 S 2 3 P 6 4 S 1 basically has an atom
1) Lithium
2) sodium
3) Potassium
4) Calcium
29. The number of protons and neutrons contained in the core of the isotope atom40 K, equally, respectively
1) 19 and 40 2) 21 and 19 3) 20 and 40 4) 19 and 21
30. Chemical element, one of the isotopes of which has mass number 44 and contains 24 neutron in the kernel - this
1) Chrome
2) Calcium
3) Ruthenium
4) Scandium
Quite difficult are for schoolchildren issues related to the laws of the flow of a chemical reaction. So, the difficulty caused a simple question:
A24 (2005, 34%) At speed chemical reaction Understand the change
1) concentration of reagent per unit of time
2) the amount of substance reagent per unit of time
3) the amount of reagent substance per unit volume
4) the amount of matter of the product in a unit of volume
Errors may be caused by the determination of the reaction rate, which is sometimes given, as a change in the "amount of a substance in a unit of volume per unit of time." But the change in the amount of substance in a unit of volume is a change in the concentration (D n / v \u003d d c).
Correct answer: 1.
Difficulties caused questions related to changes in the speed of a chemical reaction:
A24 (2005, 46%)
4Fe (TV.) + 3O 2 (gas) \u003d \u200b\u200b2Fe 2 O 3 (TV) + Q follows
1) reduce temperature
2) increase temperature
3) reduce oxygen concentration
4) increase the amount of iron
A23 (2004, 23%) To increase the reaction speed
2AGNO 3 (TV) \u003d 2AG (TV) + 3O 2 (g) + 2NO 2 (g) - 157 kJ required
1) increase the concentration of AGNO 3
2) reduce pressure in the system
3) increase the degree of shreddance of AGNO 3
4) reduce temperature
Factors affecting the rate of chemical reaction are:
Nature substances;
Temperature;
Concentration of starting materials;
Pressure of gaseous source substances;
The presence of a catalyst.
For heterogeneous reactions, factors are added as:
The size of the surface is usually associated with the degree of grinding of the substance;
The presence (intensity) of mixing.
The increase in any of these factors (except for the nature of substances) leads to an increase in the speed of the chemical reaction.
For the first question immediately define the correct answer is 2.Because the temperature increases the most common factor affecting the reaction rate. Since the reaction is heterogeneous, increasing the amount of iron substance, if it is not associated with an increase in the surface, does not lead to an increase in the reaction rate.
The second reaction is also heterogeneous, and among the proposed answers there is a degree of grinding of the substance. The greater the degree of grinding, the greater the surface of the solid, the greater the reaction rate. Other listed effects or do not affect the velocity of this reaction (1 and 2), or lead to its decrease (4). Correct answer: 3.
Possible causes of errors: schoolchildren do not take into account the heterogeneity of the system and choose the first answer; Schoolchildren are confused by the factors shifting equilibrium (answer 2), and factors affecting the reaction rate.
As noted, in 2004, issues on the energy of a chemical reaction were most difficult, for example:
A24 (2004, 22%) Exothermic is a reaction
1) MGCO 3 \u003d MGO + CO 2
2) Fe 2 O 3 + 2Al \u003d 2fe + Al 2 O 3
3) C + CO 2 \u003d 2CO
4) 2ch 4 \u003d C 2 H 2 + 3H 2
Usually, schoolchildren do not have clear criteria for determining the sign of the thermal effect on the reaction equation, do not know how to bind it to the resistance of substances, the spaffold of the process. You can recommend the following rules:
a) if the reaction proceeds spontaneously Under normal conditions, it is most likely exothermic (but for the beginning of the reaction it may be necessary to initiate). So, after the ignition, the combustion of coal proceeds spontaneously, the reaction is exothermic;
b) For resistant substances of the reaction of their formation from simple substances, exothermic, decomposition reactions are endothermic.
c) If during the reaction from less stable substances is formed more stable, exothermic reaction.
IN this case Exothermic is the reaction of almothemia, which after the preliminary ignition proceeds spontaneously, with the release of such a large amount of heat that the forming iron melts. Correct answer: 2
Difficult, especially for the participants of the 2nd wave of 2005 there were questions dedicated to the ion exchange reactions.
A27 (2004, 12.2%) The interaction of copper and hydrogen sulfide sulfate corresponds to the abbreviated ion equation:
1) Cu 2+ + H 2 S \u003d CUS + 2N +
2) CUSO 4 + 2N + \u003d Cu 2+ + H 2 SO 4
3) CUSO 4 + S 2- \u003d CUS + SO 4 2-
4) Cu 2+ + S 2- \u003d Cus
Molecular reaction equation: CUSO 4 + H 2 S \u003d CUS + N 2 SO 4
From the substances involved in the reaction, strong electrolytes is copper sulfate (soluble salt) and sulfuric acid (severe acid). These substances should be recorded in the form of ions. H 2 S ( weak Acid) and CUS (insoluble) ions in the solution are practically not formed, and should be recorded entirely. Correct answer: 1.
A typical error of schoolchildren is to determine the ability of the substance to disintegrate on the ions only on the solubility table. It seems for this reason many have chosen the answer 4.
One of the difficult questions on the topic "Chemical Equilibrium":
A25 (2005, 49%) In the CH 3 system 3 + CH 3 it "CH 3 coaxial 3 + H 2
the displacement of chemical equilibrium towards the formation of ester will contribute
1) add methanol
2) pressure increase
3) Enhance the concentration of ether
4) adding sodium hydroxide
Since the esterification reaction is carried out in a liquid state, the pressure will not affect the equilibrium position. Increasing the concentration of ether, the reaction product displays the balance towards the starting materials. The student must understand the effect of sodium hydroxide. Although directly B. reversible reaction It does not participate, but can interact with acetic acid, reduce its concentration, shifting the balance to the left.
