Question

Как узнать, к главной или побочной группе относится химический элемент, если на таблице Менделеева не указаны А и Б подгруппы (нельзы посмотреть, справа или слева расположены элементы)? Может быть, существует какая-нибудь закономерность или проще выучить элементы побочных подгрупп отдельно?

Answer 1

Справа побочная, слева главная группа. никакой закономерности нет)

Answer 2

Determining Main or Subgroup of an Element in the Periodic Table

To determine whether a chemical element belongs to the main or subgroup when the A and B subgroups are not specified on the periodic table, you can use the following methods:

1. Group and Period Numbers: - The group number of an element indicates its main group, while the period number indicates its energy level. For example, elements in group 1, 2, and 13 to 18 belong to the main group, while elements in groups 3 to 12 belong to the subgroup.

- Example: If an element is in group 15, it belongs to the main group, while if it is in group 3, it belongs to the subgroup.

- Source: Source provides a table showing the elements in groups 17 and 18, which are part of the main group.

2. Chemical Properties: - Another way to determine the main or subgroup of an element is by considering its chemical properties. Elements in the main group tend to exhibit similar chemical properties within their group, while elements in the subgroups have different properties.

- Example: Elements in group 2 (main group) generally form +2 cations, while elements in group 3 (subgroup) form +3 cations.

- Source: Source mentions the chemical properties of elements in relation to their groups.

3. Electron Configuration: - The electron configuration of an element can also provide insight into whether it belongs to the main or subgroup. Elements in the main group have s and p orbitals filled, while elements in the subgroup have d orbitals filled.

- Example: Elements in group 14 have the electron configuration ending in 4s²4p², indicating they belong to the main group.

- Source: Source discusses the electron configurations of elements in the periodic table.

By considering these methods, you can determine whether an element belongs to the main or subgroup, even when the A and B subgroups are not explicitly specified on the periodic table.