Question

Химия! Срочно! 15 баллов Выбери объяснение периодичности изменения свойств химических элементов: 1. периодичность изменения свойств обозначает, что через определённое число элементов свойства повторяются 2. свойства простых веществ, а также состав и свойства соединений элементов находятся в периодической зависимости от величины их относительных атомных масс 3. металлические свойства элементов ослабляются при возрастании относительной атомной массы

Answer 1

Ответ будет 1. В учебнике по химиии если прочитать параграф под названием "Периодическая система химических элементов Д. И. Менделеева", то там это написано

Answer 2

Конечно же вариант 1
     

Answer 3

Explanation of the Periodicity of Chemical Element Properties

The periodicity of the properties of chemical elements refers to the regular and predictable pattern in which the properties of elements change as you move across a period (horizontal row) or down a group (vertical column) in the periodic table. There are several explanations for this periodicity:

1. Repetition of Properties: The periodicity of changing properties indicates that after a certain number of elements, the properties repeat. This means that elements with similar properties occur at regular intervals in the periodic table. For example, elements in the same group tend to have similar chemical behavior and exhibit similar properties. This repetition is due to the arrangement of electrons in the atoms of these elements, which determines their chemical behavior and reactivity. [[1]]

2. Periodic Dependence on Atomic Mass: The properties of both simple substances and compounds formed by elements are dependent on the relative atomic masses of the elements. In the early development of the periodic table, Dmitri Mendeleev arranged the elements in order of increasing atomic mass and observed that elements with similar properties occurred at regular intervals. This led to the development of the modern periodic table, where elements are arranged in order of increasing atomic number. The periodicity of properties is a result of the periodic variation in electron configuration and atomic structure as atomic number increases. [[2]]

3. Weakening of Metallic Properties: As the relative atomic mass of elements increases across a period, the metallic properties of elements tend to weaken. Metallic properties include characteristics such as malleability, ductility, and electrical conductivity. This trend can be observed by comparing the elements from left to right across a period in the periodic table. As the atomic mass increases, the metallic character decreases, and elements become more nonmetallic in nature. This is due to the increasing effective nuclear charge, which attracts the valence electrons more strongly, making it more difficult for them to move freely and exhibit metallic properties. [[3]]

In summary, the periodicity of changing properties in chemical elements is a result of the repetition of properties, the periodic dependence on atomic mass, and the weakening of metallic properties as the relative atomic mass increases across a period.

I hope this explanation helps! Let me know if you have any further questions.