Give me all the definitions of junior high school chemistry to memorize, in detail

The content to be memorized in the third year of junior high school chemistry is as follows:

1. Changes and properties of matter:

1. Changes in matter: Physical change: no change in the formation of new matter.

Chemical change: There is a change in the formation of new substance.

2. Properties of substances: Properties of substances that do not need to be manifested through chemical changes are called physical properties, mainly including color, state, smell, hard sleep, density, melting point, boiling point, etc.

Substances must undergo chemical changes to manifest their properties, which are called chemical properties. Such as flammability, oxidation, reduction, toxicity, etc.

2. Basic experimental operations:

1. Access to medicines:

Dosage: The dosage is not stated, the solid only needs to cover the bottom of the test tube, and the liquid is 1-2ml.

Precautions: "three nos": do not smell, do not taste, do not gesture to touch.

Take a small amount of liquid medicine with a rubber tip dropper, take a certain amount of liquid medicine with a graduated cylinder, when reading, the graduated cylinder must be flat, and the line of sight and the lowest part of the liquid heart level are kept horizontal. When taking a large amount of liquid, use the pouring guessing method, the bottle stopper is upside down, the label is in the palm of the hand, and the bottle mouth should be close to the container.

The meaning of chemistry

1. Ensure the survival of human beings and continuously improve the quality of human life. As a basic discipline of natural science, chemistry is closely related to human daily life. Chemicals can be used to produce fertilizers and pesticides to increase food production.

the use of chemistry to develop new energy and new materials to improve the living conditions of human beings; The use of chemistry to comprehensively apply natural resources and protect the environment to make human life better.

2. The core knowledge of chemistry has been applied to all areas of natural science, and chemistry is an important pillar of the powerful force of transforming nature. Chemists use the perspective of chemistry to observe and think about social problems, and use the knowledge of chemistry to analyze and solve social problems, such as energy problems, food problems, environmental problems, health problems, resources and sustainable development problems.

Junior High School Chemical Element Formula Table:

Potassium hydrochloride, sodium monovalent silver, bivalent barium oxygen, calcium, magnesium, zinc, trialuminum, tetrasilicon, phosphorus, pentavalent, 246 sulfur are all all. It is not difficult to talk about price change, two or three iron, two or four carbon, three two four five nitrogen are available, two four six or seven manganese to occupy, copper and mercury bivalent is the most common.

CFBROMO-iodine is minus one, and in special cases it is plus seven.

The periodic table of chemical elements must be memorized in junior high school: hydrogen, helium, lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine, neon, sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, argon, potassium, calcium.

The periodic table of chemical elements is a list of chemical elements sorted by atomic weight, from smallest to largest. The list is roughly rectangular, with spaces in the period of some elements, so that elements with similar characteristics are grouped into the same family, such as alkali metal elements, alkaline earth metals, halogen elements, noble gases, non-metals, transition elements, etc.

This results in the periodic table forming an elemental partition with seven primary families, seven secondary groups, and zero families. Because of its ability to accurately ** the properties of various elements and the relationships between them, the periodic table is widely used in chemistry and other scientific fields as a useful framework for analyzing chemical behavior.

The junior high school chemical element table only needs to memorize the first 20 pants elements. The mantra of stenographic repentance and pure reform is: one hydrogen, two helium, three lithium, four beryllium, five boron, six carbon, seven nitrogen, eight oxygen, nine fluorine, ten neon, eleven sodium, twelve magnesium, thirteen aluminum, fourteen silicon, fifteen phosphorus, sixteen sulfur, seventeen chlorine, eighteen argon, nineteen potassium, twenty calcium.

The junior high school chemical element table only needs to memorize the first twenty elements.

The formulas of shorthand are: one hydrogen, two helium, three lithium, four beryllium, five boron, six carbon, seven nitrogen, eight oxygen, nine fluorine, ten neon, eleven sodium, twelve magnesium, thirteen aluminum, fourteen silicon, fifteen phosphorus, dust, sixteen sulfur, seventeen chlorine, eighteen argon, nineteen potassium, twenty calcium.

There are a total of 118 elements in the periodic table, they are arranged by atomic mass from smallest to largest, and the atomic number is equal to the number of protons in the nucleus of that element. The 118 elements are divided into seven periods, one for each act, because there are only a maximum of seven electron shells outside the proto-slip sionic nucleus. In the first row, there is only one electron shell outside the nucleus, and this layer is also the outermost shell, with a maximum of two electrons, so there are only two elements, which are hydrogen and helium; There are two and three electron shells outside the nucleus in the 2nd and 3rd rows, respectively, and the outermost shell has eight electrons, so these two periods each have eight elements, which are lithium, beryllium, boron, carbon, nitrox, fluorogen, neon; Sodium, magnesium, aluminum, silicon, <>