Who has the chemistry knowledge points summarized in junior high school chemistry, tell me

Physical Change: There is no change in the formation of new matter.

No new matter is formed macroscopically, and no new molecules are formed on the microscopic level.

It often refers to a change in the state of matter, a change in shape, a shift in position, etc.

Chemical change: There is a change in the formation of new substances, also called chemical reactions.

New substances are formed on the macroscopic level and new molecules are formed on the microscopic level.

Chemical changes are often accompanied by some reaction phenomena, such as luminescence, heat generation, gas production, color change, precipitation, etc. In some cases, reaction phenomena can be used to determine whether a chemical change has occurred or what kind of substance the product is.

Oxide: A compound composed of two elements, one of which is the element oxygen.

Oxides can be divided into metal oxides and non-metal oxides; It can also be divided into acidic oxides, basic oxides and amphoteric oxides;

Acid: A compound in which all cations ionized in solution are hydrogen ions. Acids can be divided into strong acids and weak acids; monobasic and polyacids; Oxygenated acids and anaerobic acids, etc.

Base: The cations ionized in solution are all compounds of hydroxide ions. Bases can be divided into soluble and insoluble bases.

Salt: A compound that ionizes metal cations and acid anions during ionization. Salts can be divided into normal salts, acid salts, and basic salts.

SO42- (sulfate), NO3- (nitrate), CO32- (carbonate), CLO3- (chlorate), MNO4- (permanganate), MNO42- (manganate), PO43- (phosphate), CL- (chloride), HCO3- (bicarbonate), HSO4- (bisulfate), HPO42- (monohydrogen phosphate), H2PO4- (dihydrogen phosphate), OH- (hydroxide).

Hs- (Hydrogen Thio), S2- (Sulfur), NH4+ (Ammonium or Ammonium Ion), K+ (Potassium), Ca2+ (Calcium), Na+ (Sodium), Mg2+ (Magnesium), Al3+ (Aluminum), Zn2+ (Zinc), Fe2+ (Ferro), Fe3+ (Iron), Cu2+ (Copper), Ag+ (Silver), Ba2+ (Barium).

In fact, chemistry is actually an interesting subject, not as difficult as imagined, many students lack patience, so they can't learn chemistry well, I have compiled some chemistry knowledge points, I hope it will help you.

Proton: 1 proton with 1 unit positively charged nucleus (+).

Neutrons: Uncharged atoms are not charged.

Electron: 1 electron with 1 unit negative charge.

1.There are three types of particles that make up atoms: protons, neutrons, and electrons. But not all atoms are made up of these three particles. For example, there is a hydrogen atom that has only protons and electrons, but no neutrons.

2.In an atom, the number of positive charges (nuclear charge number) carried by the nucleus is the number of charges carried by protons (neutrons are not charged), and each proton carries 1 unit of positive charge, therefore, the number of nuclear charges = the number of protons, since the number of plea in the nucleus is equal to the number of electrons outside the nucleus, the number of nuclear charges in the atom = the number of protons = the number of electrons outside the nucleus.

There are charged particles in an atom, why is the whole atom not electrical?

The atom is composed of a positively charged nucleus in the center of the atom and negatively charged electrons outside the nucleus, which in turn is composed of protons and neutrons, protons are positively charged, and neutrons are not charged; The positive charge (nuclear charge number) of the nucleus is equal to the negative charge of the electrons outside the nucleus, but the electrical properties are opposite, so the whole atom is not electrical.

This is the composition of atoms that I have compiled from my junior high school chemistry knowledge points.

Metals are usually solid, but not all metals are solids.

Metals are generally reactive and easily react with oxygen, acids, and certain salts in the air to form oxides and other compounds. For example, metal iron is easy to be corroded in humid air, and the bridge width is rusted; Metallic copper is prone to patina, etc.

Metals are usually very reactive, but some metals are very stable in nature and generally do not react with substances.

Fundamental characteristics of the displacement reaction:

Elemental + Compound === Compound + Elemental.

The common valencies of metals are: +1, +2, +3. Common +1 valent metals are: Na+, K+, Ag+, etc.;

Iron does not react with oxygen at room temperature, and in humid air, it can react with oxygen to form rust, but the rust structure is very loose and cannot prevent the outside air from continuing to react with oxygen, so it can eventually be completely corroded to form rust.

This is my junior high school chemistry knowledge point, metals and metal minerals.

Basic concepts of chemistry in junior high school.

1. Chemical change: changes in other substances are generated.

2. Physical change: no change in other substances.

3. Physical properties: properties that do not need to undergo chemical changes to manifest themselves.

Such as: color, state, density, odor, melting point, boiling point, hardness, water solubility, etc.).

4. Chemical properties: the properties of substances in chemical changes.

Such as: flammability, combustibility, oxidation, reduction, acidity and alkalinity, stability, etc.).

5. Pure substance: composed of a substance.

6. Mixture: It is composed of two or more pure substances, and each substance retains its original properties.

7. Element: A general term for a class of atoms with the same number of nuclear charges (i.e., the number of protons).

8. Atom: It is the smallest particle in chemical change, and it cannot be divided in chemical change.

Chemistry knowledge points in junior high school.

There are three methods of gas collection: the discharge method (gas that does not tolerate water), the upward air exhaust method (gas denser than air), and the downward air discharge method (gas that is less dense than air).

The three laws of conservation of mass do not change: the type of atom does not change, the number of atoms does not change, and the mass of the atom does not change.

There are three ways to change an unsaturated solution into a saturated solution or destroy it: increase the solute, decrease the solvent, and change the temperature (up or down).

There are three conditions for a metathesis reaction to occur: the formation of water, gas, or precipitation.

Three gaseous pollutants are emitted into the air: carbon monoxide, nitrogen oxides, and sulfur-hungry oxides.

Burning substances that glow white: magnesium bars, charcoal, candles.

Sorting out the key knowledge points of chemistry.

Flammable, reducing substances: hydrogen, carbon monoxide, elemental carbon.

The three gases that are flammable are: hydrogen (ideal), carbon monoxide (toxic), methane (commonly used).

There are three chemical properties of CO: limb decay flammability, reducibility, and toxicity.

Three major fossil fuels: coal, oil, and natural gas. (All mixtures).

Three ferrous metals: iron, manganese, chromium.

Three oxides of iron: ferrous oxide, ferric oxide, ferric tetroxide.

Three oxides for ironmaking: iron ore, coke, limestone.

There are three common strong acids: hydrochloric acid, sulfuric acid, and nitric acid.

There are three characteristics of concentrated sulfuric acid: water absorption, dehydration, and strong oxidation.

Three common names for sodium hydroxide: caustic soda, caustic soda, caustic soda.

Basic copper carbonate is thermally decomposed to produce three oxides: copper oxide, water (hydrogen oxide), and carbon dioxide.

1. When measuring the volume of liquid, the measuring cylinder must be placed steadily. The line of sight is level with the lowest point of the tick mark and the concave surface of the liquid in the graduated cylinder. The graduated cylinder cannot be used for heating and cannot be used as a reaction vessel. A graduated cylinder with a capacity of 10 milliliters can generally only read milliliters.

2. Gripper iron clamp and test tube clamp. The position of the iron clamp clamping the test tube should be near the mouth of the test tube 1 3. The long handle of the tube clamp, do not press your thumb on the short handle.

When clamping the test tube, the test tube clamp should be sleeved from the bottom of the test tube to the top; The clamping part is held by hand at 1 3 places near the mouth of the test tube.

3. The use of liquid drugs and the pouring method of liquid reagents: remove the cap and put it upside down on the table, (so as not to contaminate the drug). The label should be oriented towards the palm of the hand (to avoid the residual liquid flowing down and corroding the label).

Pick up the reagent bottle, put the bottle mouth close to the edge of the test tube mouth, slowly inject the reagent, pour it, close the bottle cap, label outward, and put it back in place.