concept
When the electron is collided with an atom, if the energy of the acceleration electron is large enough to put the original electron strike, the atom becomes positive, when it is used to accelerate Electronics of electrons are called ionization potentials. The ionization energy of the atom-based state (the energy required to move an electron from the base of the ground to the unlimited distance) is also referred to as ionization potential. For example, hydrogen ionization energy is equal to 13.59765 ± 0.00022 electron-volt.
Len is first measured in 1902 to measure the ionization potential. Later Pvran Hz improved and re-determine the ionization potential of many atoms.
Features
ionization is the process of electrolyte to generate free moving yin and cation in aqueous solution or melt. The electrons are excited from the base to the off atom, called ionization, and the energy required for energy is ionization potential energy. For example, the energy of the hydrogen atom is -13.6 eV (electron volt), so that the ionization potential energy of the electron ionization is 13.6 eV (ie 2.10-18 Joules).
atom is composed of a negative electrical electron with a positively charged atomic core and its surrounding electron, since the positive electrical load of the atomic core is equal to the negative electricity load of the electron, the atom is neutral. Atom's outermost The electrons of the layer are valented. The ionization is that the atom is affected by the outside world. When the accelerated electron or ion is collided with the atomic collision, the atomic electron is detached, and the atoms become a belt. One or a few positively charged ions, this is positive ions. If electron is obtained in the collision, it becomes an negative ion.
Ionization potential is an important feature of chemical elements, as the retention intensity of electrons on the atomic orbit is largely determined by the chemical properties of these elements; understanding it can more understand the compound molecules in compound molecules The distribution characteristics of electronic cloud density.
In each cycle, the ionization potential is growing, complies with certain complex laws: the lowest value i 1 is the characteristic of alkali metal, its atom core is within its own cycle It has the smallest charge, so attracting (single) one price is small; the highest elements are the eighth element (inert gas), and they are most atomic nuclear charges in their own cycle.
assay
If the amount of energy large enough to give the atom, the electrons in the atom can be ionized, which can be referred to as ionization. When the electron accelerated by the electric field, the atomic phase is accelerated, and the atomically ion can be ionization, and the potential difference is called an ionization potential. The measuring device for the ionization potential is shown in Figure 1.
In a container, there are several electrodes. The k in Fig. 1 is a hot cathode of the emission electron, G is a cylindrical metal mesh, and a cylindrical anode A cylindrical web is set, and there is a flat bottom, and the bottom of the bottom is a small hole, and there is one Layer Metal Net g 1 . In the outer side of G 1 , a thermal cathode K 1 can be emitted. The G pole maintains a certain voltage between the K (G poles and the extreme potential. Pull the air in the container, charge the gas being studied, and achieve appropriate air pressure.
experimental division is performed: First, a fixed voltage is maintained between the kg. Gradually increase the amount of electron emission of K-pole, and observe changes in the current of the Kg. As can be seen from the current meter. The initial current is rising, and later stopped. This is due to the Kg inter-optical voltage is fixed, although the K-pole emission is large, but cannot evacuate to A, so that there is a large amount of electrons around the K pole, thereby limiting the emission of K-pole electrons, so the amount of emissions cannot be Increase.
At this time, the second step of experiment is performed, and the voltage is added between K 1 g 1 , and gradually becomes larger, so K 1 The electrons emitted by the electrode are accelerated and passed through the metal network G, enters G 1 g space. At the beginning, there is no impact on the current of the kg. However, when the voltage between K 1 g 1 reaches a certain value, the KG inter-KG current will suddenly rise. The reason for this situation is due to the electron with gas of G 1 by g 1 electronically The atomic phase is charged to electrically, produce positive ions and electrons. In G 1 g network, G 1 extremely positive potential of K pole is positive, electronic lead G 1 pole, The positive ion moves toward K poles, and is neutralized with the electrons near K poles, thereby reducing the limitations of K-pole electron emission, so that the electron emission amount increases, so the Kg is also increased. Thus, the KG current suddenly increases, and it is shown that there is ionization, that is, the potential difference between K 1 1 has reached the gas ionization potential. Using this method can measure the ionization potential of many types of atoms, but atomic ionization potentials can also be calculated from the experiment of spectra.
The voltage required for one of the electron ions in the neutral atom is referred to as the first electrophototope.
Various elements have certain ionization potentials This fact indicated that the energy difference from the anion of the atom to the ionization state is certain, which is also a powerful proof of the internal energy quantization of the atomic.