THE VIDIO ABOUT RADIOAKTIF

https://www.youtube.com/watch?v=BxLXIBLD8rA



Development of Radioactivity

Development of Radioactivity  In 1895 W.C. Rontgen experiments with cathode rays. He discovered that the cathode ray tube produces a high-powered radiation that can blacken the photo film. Furthermore, the rays are named X rays. X rays do not contain electrons, but are electromagnetic waves. X-rays are not deflected by the magnetic field, and have wavelengths shorter than the wavelength of light. Based on the results of the W.C Rontgen research, Henry Becquerel in 1896 intends to investigate X rays, but by chance he found symptoms of radioactivity. In his research he found that uranium salts can damage photo films even if sealed with black paper. According to Becquerel, this is because the uranium salts can emit a ray spontaneously. This event i called spontaneous activity radio

Marie Curie was intrigued by Becquerel's findings, further with the help of her husband Piere Curie managed to separate a small number of new elements from several tons of uranium ore. The element is named radium. The Currie pair continues its research and discover that the new element it discovers has decomposed into other elements by releasing a powerful energy called radioactivity. British scientist Ernest Rutherford explains that unstable atomic nuclei (radionuclides) undergo radioactive decay. Small particles with high speed and rays spread from the nucleus of the atom in all directions. The chemists separate the rays into different streams using a magnetic field. And it turns out there are three different types of nuclear radiation that is alpha, beta, and gamma rays. All radionuclides naturally emit one or more of the three types of radiation.

2. Radioactive rays have the following properties:

1. Can penetrate paper or thin metal slabs.

2. Can ionize the illuminated gas.

3. Can blacken the film plate.

4. Causing ZnS-coated substances to fluoresce (fluorescence).

5. Can be described by the magnetic field into three beams of light, ie rays α, β,

And γ.

3. Various kinds of radioactive rays

1. Alfa rays (α)

This radiation consists of a beam of alpha particles. The alpha radiation consists of particles which are positively charged with a charge of +2 and their atomic mass. These particles are considered helium nuclei because they are similar to helium nuclei. When it penetrates the substance, the α rays produce a large number of ions. Because positively charged α particles are deflected by magnetic fields or electric fields. Alpha particles have low penetrating power. Alpha particles move at speeds between 2,000 - 20,000 miles per second, or 1 to 10 percent the speed of light.

2. Beta Rays (β)

The β ray beam consists of particles with negatively charged and β particles identical to the electrons. The beta rays have greater penetrating power but the ionizing power is smaller than the α rays. This file can penetrate aluminum paper 2 to 3 mm thick. The beta particles are also deflected by electric fields and magnetic fields, but their direction is opposite from alpha particles. In addition, β particles experience a larger deflection than particles in electric fields or in magnetic fields. This is because the β particles have a much lighter mass than the α particles

3. Gamma rays

Some processes of radioactive decay that emit α or β particles cause the nuclei to be in an energetic state, so that the next nucleus loses energy in the form of electromagnetic radiation, ie gamma rays. Gamma rays have great penetrating power and these beams are not deflected by electric fields or magnetic fields. Gamma rays have very short wavelengths.

4. Core Structure

The nucleus of atoms is composed of particles called nucleons. A nucleus known to the number of protons and neutrons is called nuclides.

5. Stability Tape

Elements with low and medium atomic numbers mostly have stable or unstable nuclides (radioactive). Examples of hydrogen atoms, protium and deuterium nuclei are stable while tritium nuclei are unstable. The tritium half-life is so short that it is not found in nature. In elements with high atomic numbers there is no stable atomic nucleus. So the factor that affects the stability of atomic nuclei is the number of appeals with protons.

The unstable nuclei tend to adjust the neutron to proton ratio to be equal to the ratio in the stability band. For nuclides with Z = 20, the ratio of neutrons to protons (n ​​/ p) is about 1.0 to 1.1. If Z increases then the neutron to proton ratio increases to about 1.5.

6. Reaction to the Core

The reaction that occurs in the nucleus of an atom is called a nuclear reaction. So nuclear reactions involve changes that do not occur in the outer shell of electrons but occur in the nucleus of the atom. Nuclear reactions have similarities and differences with ordinary chemical reactions. The nuclear reaction equation with ordinary chemical reactions, among others, as follows.

A. There is the conservation of the charge and the conservation of the mass of energy.

B. Has energizing energy.

C. It can absorb energy (endoenergic) or release energy (eksoenergik).

The difference between a nuclear reaction and an ordinary chemical reaction, such as the following.

A. The atomic number changes.

B. In the endoenergic reaction, the amount of reaction material is greater than the reactant, whereas in the eco -genergic reaction the opposite occurs.

C. The amount of matter expressed per particle is not per mole.

D. Reactions involving certain nuclides are not a mixture of isotopes.

Nuclear reactions can be written like the above example or can be expressed as follows. At the beginning the target nuclide is written, then inside the parentheses the projectile and the emitted particles are separated by a comma and at the end of the formulation are written the reaction nuclides.

an.MR