Atom of chemical element consists of a kernel and an electron shell. The kernel is the central part of atom in which almost all its weight is concentrated. Unlike an electron shell, the kernel has a positive charge.
It is required to you
- Atomic number of chemical element, Moseley's law
Instruction
1. The atomic nucleus consists of two types of particles - protons and neutrons. Neutrons are electroneutral particles, that is their electric charge is equal zero. Protons are positively charged particles and their electric charge is equal to +1.
2. Thus, the charge of a kernel is equal to quantity of protons. In turn, quantity of protons in a kernel to equally atomic number of chemical element. For example, the atomic number of hydrogen - 1, that is a kernel of hydrogen consists of one proton has a charge +1. The atomic number of sodium - 11, a charge of its kernel is equal to +11.
3. At alpha decay of a kernel its its atomic number decreases by two at the expense of emission alpha particles (helium atomic nuclei). Thus, the quantity of protons in the kernel which experienced alpha decay also decreases by two. The beta decay can occur in three different types. In case of disintegration "beta minus" the neutron turns into a proton at emission of an electron and antineutrino. Then the charge of a kernel increases by unit. In case of disintegration "beta plus" the proton turns into a neutron, a positron and nytrino, the charge of a kernel decreases by unit. In case of electronic capture the kernel charge also decreases by unit.
4. The charge of a kernel can be determined by the frequency of spectral lines of characteristic radiation of atom also. According to Moseley's law: sqrt(v/R) = (Z-S)/n where v is the spectral frequency of characteristic radiation, R is Ridberg's constant, S is a constant of shielding, n is the main quantum number. Thus, Z = n*sqrt(v/r)+s.