What are the pre study methods for college chemistry?

There is a mantra for the first cycle: hydrogen helium - aggression.

The second cycle: lithium, beryllium, boron, carbon, nitrogen, oxygen, fluorine, neon -- carp skin holding carbon, eggs and milk The third cycle: sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chlorine, argon -- the beautiful Guilin has green teeth (the beautiful ghost shows green teeth).

Fourth cycle: potassium, calcium, scandium, titanium, vanadium, chromium, manganese -- marrying Kangtai counter-revolutionary, iron, cobalt, nickel, copper, zinc, gallium, germanium -- iron, pinching, arsenic, selenium, bromine, krypton -- anger, shock.

Fifth cycle: rubidium, strontium, yttrium, zirconium, niobium -- so tell you molybdenum, technetium, ruthenium -- unbelievable.

Rhodium, palladium, silver, cadmium, indium, tin, antimony, --Laojiao, Yinge, Tellurium, iodine, xenon, --Location immortal.

Sixth cycle: cesium, barium, lanthanum, hafnium--color), color shell (shell), blue (color), river tantalum, tungsten, rhenium, osmium -- but (see) black (crow) (lead) goose iridium, platinum, gold, mercury, stone, lead, -- a white towel for it to hold bismuth, polonium, astatine, radon -- will not love winter (day).

The seventh cycle: francium, radium, actinium -- it's very simple, it's --- lightning protection!

Valence: One price please donkey feet take silver, (monovalent hydrochloride potassium sodium silver) bivalent sheep Gaimei vest. (divalent oxygen, calcium, magnesium, barium, zinc).

Monovalent potassium, sodium, hydrochloride, silver, divalent oxygen, calcium, barium, magnesium, zinc.

3. Aluminum, 4 silicon, pentavalent phosphorus, 23 iron, 24 carbon.

Nitrogen, copper, mercury, and bivalent are the most common in the first to pentavalent currencies.

Positive copper, potassium, sodium, silver, copper, magnesium, calcium, barium, zinc.

3. Aluminum, 44 silicon, 46 sulfur, 245, nitrogen, 35 phosphorus.

157 chloro23 ferric 2467 manganese is positive.

Carbon has positive four and positive two, and then keep the negative price in mind.

Negative iodine monobromo, with fluorochlorofluorocarbon, negative dioxysulfur, trinitrogen, phosphorus.

Common atomic group valence decision in junior high school:

Negative hydroxide mononitrate, negative disulfate carbonate, and negative triphosphate, only ammonium is positive monohydrohelium, lithium beryllium boron, carbon, nitrogen, oxyfluorone. Sodium, magnesium, aluminum, silicon, phosphorus, sulfur, chloride, argon, potassium, calcium.

To remember the valency, we often use the following formula:

Monovalent potassium hydrochloride, sodium silver, bivalent calcium, magnesium, barium oxygen, zinc. Two copper, three aluminum, four seven manganese, two four hexasulfur, two four carbon, three valent nitrogen and phosphorus, iron have two or three to remember.

The order of metal activity can be memorized according to the following formula:

Potassium, calcium, sodium, magnesium, aluminum, zinc, iron, tin, lead, hydrogen, copper, mercury, silver, platinum.

It can be programmed as a slip or memorized according to the characteristics of period or family ordinal.

Physical change: No change in the formation of other substances (shape, state, dissolution, volatilization, diffusion, adsorption, light emittion, ......etc.).）

Chemical changes: There are changes in the production of other substances (combustion, rusting of steel, food decay, grain brewing, animal and plant respiration, photosynthesis, ......).）

In the process of development, many branches of chemistry at different levels are derived according to the different types of molecules studied, research methods, goals, and tasks. Before the 20s of the 20th century, chemistry was traditionally divided into four branches: inorganic chemistry, organic chemistry, physical chemistry and analytical chemistry. After the 20s, due to the rapid development of the world economy, the birth of the electronic theory of chemical bonds and quantum mechanics, the rise of electronic technology and computer technology, chemical research has obtained new means in theory and experimental technology, resulting in the rapid development of this discipline since the 30s, and a new look has emerged.

The content of chemistry is generally divided into five categories: biochemistry, organic chemistry, polymer chemistry, applied chemistry and chemical engineering, physical chemistry, and inorganic chemistry, with a total of 80 items, and actually includes seven sub-disciplines.

According to the development of chemistry and its interpenetration with astronomy, physics, mathematics, biology, medicine, geoscience and other disciplines, chemistry can be classified as follows:

Specific sub-disciplines. Inorganic chemistry.

Elemental Chemistry, Inorganic Synthetic Chemistry, Inorganic Polymer Chemistry, Inorganic Solid Chemistry, Coordination Chemistry (i.e., Complex Chemistry), Isotope Chemistry, Bioinorganic Chemistry, Organometallic Chemistry, Metalloenzyme Chemistry, etc.

Organic chemistry. General Organic Chemistry, Organic Synthetic Chemistry, Metallic and Non-metallic Organic Chemistry, Physical Organic Chemistry, Bioorganic Chemistry, Organic Analytical Chemistry.

Physical chemistry. Structural Chemistry, Thermochemistry, Chemical Thermodynamics, Chemical Kinetics, Electrochemistry, Solution Theory, Interface Chemistry, Colloidal Chemistry, Quantum Chemistry, Catalysis and Its Theory, etc.

Analytical chemistry. Chemical analysis, instrumentation and new technology analysis. Including performance determination, monitoring, various spectroscopic and photochemical analysis, various electrochemical analysis methods, mass spectrometry analysis, various electron microscopy, imaging and morphology analysis methods, ** analysis, activity analysis, real-time analysis, etc., various physical and chemical properties and physiological activity detection methods, extraction, ion exchange, chromatography, mass spectrometry and other separation methods, separation and analysis coupling, synthesis separation analysis triple use, etc.

2] Polymer Chemistry.

Natural Polymer Chemistry, Polymer Synthetic Chemistry, Polymer Physical Chemistry, Polymer Applications, Polymer Physics.

Nuclear chemistry. Radioactive Element Chemistry, Radioanalytical Chemistry, Radiation Chemistry, Isotope Chemistry, Nuclear Chemistry.

Biochemistry. General Biochemistry, Enzymes, Microbial Chemistry, Phytochemistry, Immunochemistry, Fermentation and Bioengineering, Food Chemistry, Coal Chemistry, etc.

Other marginal disciplines related to chemistry include: geochemistry, ocean chemistry, atmospheric chemistry, environmental chemistry, cosmochemistry, interstellar chemistry, etc.