Knowledge expansion
I. Chemical properties
The chemical properties of an element are determined by its atomic structure. The distribution of electrons outside the nucleus and the number of protons inside the nucleus determine the chemical properties of elements. The atoms of elements form chemical bonds through * * * electron pairs, and these chemical bonds can make elements combine with each other to form compounds. The chemical properties of an element can usually be described by its atomic number, atomic weight, ionic radius and electronegativity.
Second, the physical properties
The physical properties of elements refer to their macroscopic manifestations, including color, state, melting point, boiling point, density and so on. These properties are determined by the atomic structure and molecular structure of elements. For example, metal elements usually have metallic luster and good electrical and thermal conductivity, because there are fewer electrons in the outer layer of metal atoms and their interaction is weak, so they can move and conduct heat and current freely.
Third, the biological role.
In organisms, elements are one of the basic substances that constitute organisms. Many elements play a vital role in the survival and reproduction of organisms. For example, carbon, hydrogen, oxygen and nitrogen are the main elements that make up organisms, and they make up various tissues and organs of organisms.
In addition, some trace elements such as iron, zinc and copper also play a vital role in the growth and development of organisms. For example, iron is the main component of hemoglobin and participates in oxygen transport and cell respiration; Zinc is an auxiliary factor of many enzymes, which is involved in cell metabolism and gene expression. Copper is an auxiliary factor of many enzymes, which is involved in the formation of cell wall and the stability of cell membrane.
To sum up, elements play a vital role in nature. It has the characteristics of chemical properties, physical properties and biological functions. The properties and functions of elements are determined by their atomic and molecular structures. In organisms, elements are one of the basic substances that constitute organisms. They participate in various physiological processes of organisms and play a vital role in maintaining the life activities of organisms.