Matter, atoms, and isotopes
Release time:2024/4/12
Tourist volume:1641
The various objects that exist in nature, big like planets in the universe and small like cells in the body, are all composed of various different substances.
Matter is composed of countless small particles, which are called "atoms". Several atoms can also form more complex particles called molecules. Like water, it is formed by the combination of two hydrogen atoms and one oxygen atom into a water molecule. Infinite numbers of water molecules gather together, forming macroscopic water.
Although atoms are small, they still have complex structures. An atom is composed of a nucleus and a certain number of electrons. The atomic nucleus is at the center and positively charged. Electrons move around atomic nuclei in specific orbits and are negatively charged. The positive and negative charges of the entire atom are equal and neutral. What is the situation inside the atomic nucleus? Simply put, an atomic nucleus is composed of a certain number of protons and neutrons. The number of neutrons is slightly higher than the number of protons, and there is a certain proportion between the two.
The sum of the number of protons and neutrons contained in an atom is called its mass number. It is also the mass number of the atomic nucleus. To summarize briefly:
Nuclear neutrons (uncharged, number=mass number - atomic number)
Atomic protons (positively charged, equal in number to electrons)
Electrons (small in mass, negatively charged, equal in number to protons, known as atomic numbers)
The chemical properties of an atom depend solely on the number of electrons outside the nucleus, that is, on its atomic number. We refer to atoms with the same atomic number as elements.
Some atoms, although they have the same atomic number, have different numbers of neutrons, and their chemical properties are completely the same. And atomic nuclei have different characteristics. For example, 11H, 21H, and 31H are the three isotopes of elemental hydrogen. For example:
59CO and 60CO are two isotopes of the element cobalt.
235U and 238U are two isotopes of elemental uranium
107 elements have been discovered in nature, with over 4000 isotopes.
There are slightly more neutrons in the nucleus than protons. To be precise, there should be an appropriate ratio between the number of protons and neutrons (such as a ratio of about 1:1 for light nuclei and about 1:15 for heavy nuclei). Only such atomic nuclei are stable, and this isotope is called a stable isotope. If there are too many or too few protons, that is, too few or too many neutrons. Atomic nuclei are often unstable and can spontaneously undergo changes, releasing both radiation and energy. This type of nucleus is called a radioactive nucleus. The atoms it forms are called radioactive isotopes, such as 59CO being a stable isotope and 60CO being a radioactive isotope.
Radioisotopes are divided into two types: natural and artificial. Natural is what can be observed in nature, such as uranium, thorium, radium and its derivatives, potassium, calcium, and so on. Artificial is created through artificial methods, such as using particles generated by a reactor or accelerator to strike the nucleus, causing a nuclear reaction and causing a change in the number of protons (or neutrons) inside the nucleus. To generate radioactive isotopes, 60CO is to irradiate 59CO in a reactor. After absorbing a neutron, 60CO becomes an artificial radioactive isotope.
Matter is composed of countless small particles, which are called "atoms". Several atoms can also form more complex particles called molecules. Like water, it is formed by the combination of two hydrogen atoms and one oxygen atom into a water molecule. Infinite numbers of water molecules gather together, forming macroscopic water.
Although atoms are small, they still have complex structures. An atom is composed of a nucleus and a certain number of electrons. The atomic nucleus is at the center and positively charged. Electrons move around atomic nuclei in specific orbits and are negatively charged. The positive and negative charges of the entire atom are equal and neutral. What is the situation inside the atomic nucleus? Simply put, an atomic nucleus is composed of a certain number of protons and neutrons. The number of neutrons is slightly higher than the number of protons, and there is a certain proportion between the two.
The sum of the number of protons and neutrons contained in an atom is called its mass number. It is also the mass number of the atomic nucleus. To summarize briefly:
Nuclear neutrons (uncharged, number=mass number - atomic number)
Atomic protons (positively charged, equal in number to electrons)
Electrons (small in mass, negatively charged, equal in number to protons, known as atomic numbers)
The chemical properties of an atom depend solely on the number of electrons outside the nucleus, that is, on its atomic number. We refer to atoms with the same atomic number as elements.
Some atoms, although they have the same atomic number, have different numbers of neutrons, and their chemical properties are completely the same. And atomic nuclei have different characteristics. For example, 11H, 21H, and 31H are the three isotopes of elemental hydrogen. For example:
59CO and 60CO are two isotopes of the element cobalt.
235U and 238U are two isotopes of elemental uranium
107 elements have been discovered in nature, with over 4000 isotopes.
There are slightly more neutrons in the nucleus than protons. To be precise, there should be an appropriate ratio between the number of protons and neutrons (such as a ratio of about 1:1 for light nuclei and about 1:15 for heavy nuclei). Only such atomic nuclei are stable, and this isotope is called a stable isotope. If there are too many or too few protons, that is, too few or too many neutrons. Atomic nuclei are often unstable and can spontaneously undergo changes, releasing both radiation and energy. This type of nucleus is called a radioactive nucleus. The atoms it forms are called radioactive isotopes, such as 59CO being a stable isotope and 60CO being a radioactive isotope.
Radioisotopes are divided into two types: natural and artificial. Natural is what can be observed in nature, such as uranium, thorium, radium and its derivatives, potassium, calcium, and so on. Artificial is created through artificial methods, such as using particles generated by a reactor or accelerator to strike the nucleus, causing a nuclear reaction and causing a change in the number of protons (or neutrons) inside the nucleus. To generate radioactive isotopes, 60CO is to irradiate 59CO in a reactor. After absorbing a neutron, 60CO becomes an artificial radioactive isotope.
