The quantum mechanics shows that the electron can be located in any point near an atomic nucleus, but the probability of its stay in different points is various. Moving in atom, electrons form an electronic cloud. Those places in which they are most often are called orbitals. The general energy of an electron on an orbital is defined by the main quantum number n.
It is required to you
- - name of substance;
- - Mendeleyev's table.
Instruction
1. The main quantum number accepts the whole values: n = 1, 2, 3, …. If n= ∞, means it that energy of ionization – the energy sufficient for its separation from a kernel is reported to an electron.
2. Within one level the electrons can differ in subtotals. Such differences in a power condition of electrons of one level are reflected collateral quantum number l (orbital). It can accept values from 0 to (n-1). Values l are usually symbolically presented by letters. The form of an electronic cloud depends on value of collateral quantum number.
3. The movement of an electron on the closed trajectory provokes emergence of magnetic field. The condition of an electron caused by the magnetic moment is characterized by magnetic quantum number of m(l). This third quantum number of an electron. It characterizes its orientation in space of magnetic field and accepts the range of values from (-l) to (+l).
4. In 1925 the scientists assumed presence at an electron a back. Under backs understand own moment of an impulse of an electron which is not connected with its three-dimensional motion. The spin number of m(s) can accept only two values: +1/2 and-1/2.
5. According to Paulie's principle, in atom there cannot be two electrons with an identical set of four quantum numbers. At least one of them has to differ. So, if the electron is in the first orbit, for it the main quantum number of n=1. Then l=0, m(l)=0 is unambiguous, and for m(s) there are two possible options: m(s)= +1/2, m (s)=-1/2. For this reason at the first power level there can be no more than two electrons, and they have different spin number.
6. On the second orbital the main quantum number of n=2. The collateral quantum number accepts two values: l=0, l=1. The magnetic quantum number of m(l) =0 for l=0 also accepts values (+1), 0 and (-1) for l=1. For each of options there are still about two spin numbers. So, the greatest possible number of the electrons which are at the second power level is equal to 8.
7. For example, at noble gas of neon two power levels are completely filled with electrons. Total number of electrons of neon equals 10 (2 from the first level and 8 from the second). This inert gas, does not react with other substances. Other substances, entering chemical reactions, seek to acquire structure of noble gases.