1. Except for the main product of lithium burning in air, which is Li,0, the main products of other alkali metals burning in air are not ordinary oxides M20. Common oxides of these alkali metals can be generated in air with insufficient oxygen content, but the conditions are difficult to control and it is difficult to produce purer products. Ordinary oxides of alkali metals other than lithium can be prepared by reducing the peroxide, nitrate or nitrite of an alkali metal element or azide in a vacuum. 2. Ordinary oxides of alkaline earth metals can be prepared by reducing their carbonates Prepared by thermal decomposition of hydroxide, nitrate or sulfate. 3. The color of ordinary oxides of alkali metals generally gradually deepens from Li0 to Cs20: Li20 is white, Na,0 is white, K,0 is gray, Rb,0 is yellow-brown, and Cs,0 is yellow-orange. Common oxides of alkaline earth metals are white. 4. The general trend of thermal stability of common oxides is that the same family decreases from top to bottom, and the melting point also decreases in this order.

1. Among alkali metal and alkaline earth metal elements, other elements except beryllium can form peroxides. 2. Peroxide is a powdery solid and easily absorbs moisture. It reacts with water or dilute acid to generate hydrogen peroxide. 3. Peroxides can be used as oxidants, oxygen generators and bleaching agents. 4. Peroxide reacts with CO to release oxygen. 5. Peroxide has strong oxidizing properties. 6. Peroxide also has reducing properties. When encountering strong oxidants, it will show reducing properties.

1. Superoxide contains superoxide ion 02, which has one more electron than 0. In addition to a σ bond formed between the two oxygen atoms, there is also a three-electron π bond with a bond order of 1.5. Because of its single electron, superoxide ions are paramagnetic. 2. The melting points of alkali metal superoxides increase from top to bottom in the same family. 3. Superoxide is a strong oxidizing agent and reacts violently with water or other protic solvents to generate oxygen and hydrogen peroxide. 4. Superoxide decomposes into oxides and oxygen at high temperatures. 5. Superoxide also releases CO2 when it reacts with it. oxygen So an important use of superoxide is as a source of oxygen.

1. The oxychlorides of alkali metals and alkaline earth metals are all white solids. Be(OH) is an amphoteric hydroxide, and the other hydroxides are alkaline. 2. Alkali metal hydroxides are easily soluble in water and easily absorb moisture in the air. They release a large amount of heat when dissolved in water. Except for lithium hydroxide, which has a slightly lower solubility, the other alkali metal hydroxides can form very concentrated solutions at room temperature. 3. The solubility of alkaline earth metal hydroxides in water is much smaller, and the solubility increases from top to bottom in the same family. Be(OH)₂ and Mg(OH): are difficult to dissolve in water, and the solubility of other alkaline earth metal hydroxides is also small.

1. Except for lithium, alkali metal salts are ionic compounds, most of which are easily soluble in water. Strong acid salts of lithium are easily soluble in water, while some weak acid salts of lithium have poor solubility in water. Other alkali metals have less insoluble salts and slightly soluble salts

1. Alkaline earth metal salts are mostly ionic compounds. Salts formed by alkaline earth metals and -1-valent anions (except F) are generally easily soluble in water The solubility of salts formed by alkaline earth metals and anions with high negative charge is generally small.

1. Among alkali metal and alkaline earth metal halides, the most important ones are NaCl, MgCl2 and CaCl2. 2. NaCl is also widely used in food processing, petroleum industry, textile industry, etc. The amount of NaCl used as a road snow melting agent is also quite large. 3. The aqueous solution of MgCl2 is commonly known as brine. It is used in the processing of soy products because it can coagulate proteins. MgCl2 is an important chemical raw material and is widely used in organic synthetic chemistry. MgCl2 solution has a low freezing point, so it is often used as a snow melting agent.

1. NaCl is also widely used in food processing, petroleum industry, textile industry, etc. The amount of NaCl used as a road snow melting agent is also quite large. 2. Alkali method and combined alkali production method. The ammonia-alkali method was proposed by the Belgian Solvny in 1862, also known as the Solvny alkali production method. The combined alkali production method was invented by Chinese scientist Hou Debang in 1942. 3. Sodium bicarbonate (NaHCO,) commonly known as baking soda, is widely used in the food industry. 4. NaHCO is an important chemical raw material. It can be easily dehydrated and converted into Na2CO when heated. Calcium carbonate (CaCO,) is used as an additive in the production of coatings. The chemical composition of limestone in nature is CaCO, and its high-temperature decomposition products, CaO and CO, are important chemical raw materials.

The main products of the combustion of lithium and magnesium in oxygen are ordinary oxides

The solubility of lithium and magnesium hydroxides, LiOH and Mg(OH), is very small, while other alkali metal hydroxides are easily soluble in water. The fluorides, carbonates, and phosphates of lithium and magnesium are all insoluble salts, while the fluorides, carbonates, and phosphates of other alkali metals are easily soluble in water. For example, the solubility of sodium fluoride is about 10 times that of lithium fluoride, and the solubility of sodium phosphate is about 200 times that of lithium phosphate.

The products of thermal decomposition of lithium nitrate and magnesium nitrate are ordinary oxides of metals, nitrogen dioxide and oxygen, while the products of thermal decomposition of other alkali metal nitrates are nitrite and oxygen.

Both metal lithium and magnesium can react directly with nitrogen to form nitrides, while other alkali metals cannot