Can gas conduct electricity? Which metals do not conduct electricity?

Under normal circumstances, gas molecules are electrically neutral, but under the irradiation of radioactive elements on the ground and the action of ultraviolet and cosmic rays, etc., there are more or less always some gas molecules or atoms that are ionized, that is, the gas molecules or atoms that were originally electrically neutral are separated into an electron and a positively charged ion. In addition, in some lamps, the energized filament also emits electrons. When a certain voltage is added between the electrodes at both ends of the lamp, the applied voltage forces these electrons and positive ions to move towards the anode and cathode, but the number of positive ions and electrons in the lamp is very small, so the current formed is very weak and can be ignored under normal circumstances.

However, if the gas in the lamp is quite thin but not vacuum, and the voltage applied to the electrodes at both ends of the lamp is high enough, the electrons can get a lot of kinetic energy in the process of moving towards the anode, and when they collide with the neutral gas, they can ionize the neutral molecules, which is the so-called collision ionization. At the same time, when the positive ions move towards the cathode, they may also shoot electrons from the surface of the cathode because they hit the cathode at a great speed, and this phenomenon is called secondary electron emission. Collisional ionization and secondary electron emission cause a large number of electrons and positive ions to appear in the gas in a very short period of time.

These electrons and cations move in opposite directions under the action of external voltage. There is an electric current passing through the gas. Common gas discharge lamps, such as fluorescent lamps, neon lamps, high-pressure mercury lamps, xenon lamps, etc., are filled with a certain amount of gas, and when a certain voltage is added to both ends, there is an electric current flowing through the gas.

Gases at atmospheric pressure are not easy to conduct electricity, like air is a good insulating substance, and it is generally non-conductive. The process that turns these gases from non-conductive to conductive is called gas breakdown. Lightning in the sky during a thunderstorm is formed by the breakdown of air.

Typically, gas conduction occurs in a rarefied gas. Atmospheric pressure gases do not conduct electricity easily, and gas currents cannot be generated in relatively high vacuums because electrons and ions are not easy to touch neutral particles. The ionization and conduction of the above-mentioned gases are all self-excited discharges.

However, this collisional ionization alone cannot sustain the self-excited discharge for a long time, because all the electrons produced by the collision have to move towards the anode, and when the anode is reached, it stops. In order to maintain the discharge for a long time, the cathode must be continuously supplied with electrons. Generally, the cathode is equipped with a filament that emits electrons.

In general, metals are good conductors (room temperature, standard state).

Gases can be broken down at high pressures and conduct electricity, such as lightning.

Some metals such as GE are semiconductors.

Gas does not. Metals are electrically conductive.

At a certain humidity, water vapor is fine.

There is no metal that does not conduct electricity, and metal is a substance with shiny, malleable, easy to conduct electricity, heat and other properties. Since the electrons of the metal tend to detach, it has good electrical conductivity. In addition, metal elements are usually positively charged in compounds, but when the temperature is higher, the resistance will increase because of the thermal ** hindrance of the nucleus.

Metals are divided into two types: reactive metals and passivation metals. According to the order of metal activity, pre-hydrogen metals are called active metals, and post-hydrogen metals are passivation metals. The metals with the weakest electrical conductivity, i.e., greater resistance, are bismuth or germanium.

The substances that do not conduct current in life are: plastics, rubber, glass, ceramics, various natural mineral oils, silicone oils, trichlorobiphenyl, air, carbon dioxide, sulfur hexafluoride and so on.

Metal conductivity is the movement of (relative) free electrons in a metal crystal between the gaps formed between metal ions. That is, there are channels in the metal that allow electrons to move, and because the metal ions in the metal crystal are constantly moving (vibrating), these channels are curved and appear in narrow areas at any time.

Different solids have different conductive properties, and their conductivity is usually measured by conductivity. Conductivity is defined as the ratio of the electric field strength e applied to a solid to the current density j within a solid.

Experimental studies have shown that the conductance of solids under a not too strong electric field usually obeys Ohm's law, that is, the current density is proportional to the electric field strength and has nothing to do with the electric field strength. For cubic crystals or amorphous materials, conductivity is isotropic and is a scalar quantity.

In general, conductivity may be anisotropic and should be expressed as a second-order tensor. The unit of electrical conductivity is s m. In many cases, the reciprocal of conductivity is a quantity that is easier to use, called resistivity, expressed in ·m.

Analysis: First, clarify the difference between metals and non-metals.

Chemically, metals are connected by metallic bonds, while non-metals are connected by ionic bonds or covalent bonds. From the physical properties, metals are generally conductive, metallic, malleable, and most of them are solids, only mercury is liquid at room temperature. Non-metals are mostly insulators, and only a few non-metals are conductors (carbon) or semiconductors (silicon).

However, due to the rapid development of science and technology, the difference between them is becoming less and less obvious.

The development of nanotechnology has made the distinction between metals and non-metals smaller and smaller.

Metals are generally conductive, and common metal elements are not non-conductive.

However, this is not necessarily the case if various materials are made according to modern processes, such as nanomaterials.

It can be seen that there are non-conductive metals.

Common substances that cannot conduct electricity are: rubber, glass, plastic, ceramics, oil, pure water, dry paper, dry wooden sticks, dry air, etc.

Additional Knowledge: Conductors and Insulators:

a.Conductor: Some objects are good at conducting electricity, which is called conductorFor example: metals, human body, earth, graphite, acids, alkalis, salt water solutions, etc. are all conductors.

b.Insulator: Some objects are not good at conducting electricity called insulators, such as: rubber, glass cracks, plastics, ceramics, oil, pure water, dry paper, dry wooden sticks, dry air, etc. are insulators.

c.Conductivity vs Insulation Explained: Reasons Why Conductors Conduct Electricity:

There is a charge in the conductor that can move freely (the conduction of the metal is due to the presence of a large number of free electrons in the metal (rubber); Causes of insulator insulation: Charges are almost all bound within the atomic range and cannot move freely.

d.There is no clear boundary between a conductor and an insulator, and after a change in conditions, an insulator can become a conductor and a conductor can become an insulator. For example, heating causes some of the electrons in the insulator to break free from the atoms and become free charges, at which point the insulator becomes a conductor.

Metal contains a large number of free electrons, and the directional motion of electrons forms an electric current, while plastic has no electrons that can move freely, so metals can conduct electricity, and plastic covers do not conduct electricity.

The reason why metals can conduct electricity is that there are free electrons around the ion nucleus that make up metal molecules, and when there is voltage, the free electrons move towards the positive electrode of the voltage after being charged, and the directional movement of the electrons forms an electric current. In this way, the metal conducts the current through it, and due to the different metal elements, the number of free electrons outside the nucleus is different, and this difference reflects the different conductivity of different metals.

The reason for conducting electricity is due to the directional movement of the free charge. There are a large number of free electrons in metals, while there are almost no free electrons in plastic wood, therefore, metals can conduct electricity, while plastics do not.