Summary of inversion law of periodic law of elements

With the increase of atomic number, the properties of elements are periodically changing:

In the same period, the metallic properties of elements decrease from left to right, and the nonmetallic properties increase from left to right;

In the same family, the metallic properties of elements increase from top to bottom, and the nonmetallic properties decrease from top to bottom;

In the same period, the highest positive oxidation number of elements increases from left to right (except those without positive valence), and the lowest negative oxidation number increases gradually from left to right;

the elements in the same family have similar properties.

the above rules are not applicable to rare gases.

In addition, there are some criteria for judging the metallic and nonmetallic nature of elements, which can be used as a supplement to the periodic law of elements:

The stronger the reducibility of an element, the stronger the metallicity; The stronger the oxidation of simple substance, the stronger the nonmetal.

The stronger the basicity of the highest valence hydroxide of an element, the stronger the metallicity of the element; The stronger the acidity of the highest valence hydroxide, the stronger the nonmetallic nature of the elements.

the more stable the gaseous hydrides of elements are, the stronger the nonmetallic properties are.

There are also some conclusions based on the periodic law of elements:

The stronger the metallicity of an element, the smaller its first ionization energy; The stronger the nonmetal, the greater the first electron affinity.