Question

Помогите 7 класс валестность

Answer 1

Валентность-способность атома соединяться с определённым числом других атомов.

Answer 2

Valence Electrons in 7th Grade

Valence electrons are the electrons located in the outermost shell of an atom. They are responsible for the chemical properties and reactivity of an element. To determine the valence electrons of an atom, you can look at its electron configuration.

The electron configuration of an atom describes how its electrons are distributed among its various energy levels and orbitals. In the case of the 7th grade, you are likely studying the electron configurations of elements up to the 7th period of the periodic table.

The electron configuration of an element can be determined by using the periodic table. Each period represents a different energy level, and each group represents a different number of valence electrons. For example, elements in Group 1 have 1 valence electron, elements in Group 2 have 2 valence electrons, and so on.

To determine the number of valence electrons for elements in the 7th period, you can look at the group number. For example, elements in Group 7 (also known as Group VIIA or Group 17) have 7 valence electrons. Elements in Group 8 (also known as Group VIIIA or Group 18) have 8 valence electrons, except for helium, which has 2 valence electrons.

It's important to note that the valence electrons of transition metals, which are located in the d-block of the periodic table, can be a bit more complex to determine. Transition metals have valence electrons in both the outermost s orbital and the d orbitals. For example, the element manganese (Mn) has an electron configuration of 1s2 2s2 2p6 3s2 3p6 4s2 3d5. In this case, the 3d electrons are considered the valence electrons.

In summary, the number of valence electrons for elements in the 7th period of the periodic table can be determined by looking at the group number. Elements in Group 7 have 7 valence electrons, elements in Group 8 have 8 valence electrons (except for helium), and transition metals have valence electrons in both the outermost s orbital and the d orbitals.

Note: The information provided above is based on general knowledge about valence electrons and the periodic table. For more specific information about the electron configurations of individual elements, it is recommended to consult a reliable chemistry textbook or online resource.