(1) On the Properties of Sodium

Sodium, a metallic element, is soft and can release hydrogen from water. The content of sodium 1 in the earth's crust is 2.83%, ranking sixth. It mainly exists in the form of sodium salts, such as salt (sodium chloride), Chilean saltpeter (sodium nitrate) and soda ash (sodium carbonate). Sodium is also one of the main components of human muscle and nerve tissue. In ancient Chinese, ".

chemical property

The outermost layer of sodium atom has only 1 electron, which is easy to be lost. So the chemical properties of sodium are very active. When it reacts with other substances, its valence increases from 0 to+1. It's metal.

Reaction of sodium with oxygen

At room temperature, 4Na+O2 = 2Na2O (white solid)

After ignition, 2na+O2 = Na2O2 (light yellow powder)

★ After sodium is ignited in the air, it quickly melts into a shiny ball, giving off a yellow flame and generating sodium peroxide. Sodium peroxide is more stable than sodium oxide, which can combine with oxygen to form sodium peroxide. The chemical equation is: 2Na2O+O2=2Na2O2.

2. Sodium can directly react with nonmetals such as halogen, sulfur, phosphorus and hydrogen to generate corresponding compounds, such as

2Na+Cl2=2NaCl

2na+s = Na2S (sodium sulfide) (sodium and sulfide will explode when combined with grinding).

3. The reaction of sodium with water

Add some water to the beaker, drop a few drops of phenolphthalein solution, and then put a small piece of sodium into the water.

The observed phenomena and the conclusions drawn from them are as follows:

1. Sodium floats on the water (the density of sodium is less than that of water).

2. Sodium melts into a shiny ball (sodium reacts with water to release heat, and sodium has a low melting point).

3. Sodium swims around on the water (producing gas)

Reaction of sodium with water

4. Make a hissing sound (generate gas and react violently)

5. The water dripping with phenolphthalein test solution in advance turns red (produces alkali).

reaction equation