There are 118 elements in D. I. Mendeleev's periodic system. Let's talk about one of them, standing in 8th place - about oxygen. So what is this substance? Let's get acquainted with the physical and chemical properties of oxygen.
Oxygen (O) is a colorless and odorless gas. It was opened in 1772-1774. The name, which is still relevant today, was given to the element by the creator of the first nomenclature of chemical compounds, A. L. Lavoisier, who considered oxygen to be an integral part of acids. Hence the name of the gas - Oxygene (sour).
The volume of oxygen in dry air is 20.9%. It contains 47.3% in the earth's crust in the form of various compounds.
In industry, oxygen is obtained by fractional distillation of liquid air or water electrolysis. The laboratory uses methods of thermal decomposition of substances rich in this element.
Describe the physical properties of matter:
- atom number is 8;
- the mass of an atom is 15.9994 a. e. m.;
- volume of an atom - 10, 89-10-3 m3/mol;
- atomic radius - 0.066 nm;
- electronic configuration - 2s22p4;
- electronegativity - 3, 5;
- specific heat capacity of oxygen - 0.920 kJ/(kgK);
- It consists of three stable isotopes 16O, 17O and 18O.
Isotopes of oxygen and other elements are varieties of atoms of the element under consideration that have the same atomic numbers, but different mass numbers.
The specific heat capacity of oxygen and other elements is a value that is a numerical value equal to the amount of heat that must be transferred to the mass of the substance taken in order to change its temperature by one.
Oxygen is a very active element. It is able to react with almost all elements of the Periodic Table (with the exception of inert or noble gases). In such an interaction, oxides are formed. This occurs when the elements are directly combined with oxygen or when various oxygen-containing compounds are heated. The resulting oxides are thermally stable.