Question

Три элемента принадлежат к одной группе элементов периодической системы. Сумма атомных номеров двух крайних из них равна 76. Нитрат, образованный средним из этих элементов, используют для окрашивания огней фейерверка в красный цвет. Назовите эти элементы, определите их положение в периодической системе. Охарактеризуйте строение атомов этих элементов и предскажите изменение свойств с увеличением их атомной массы. Какие природные соединения этих элементов вам известны?

Answer 1

Elements Belonging to the Same Group in the Periodic Table

Three elements belong to the same group in the periodic table, and the sum of the atomic numbers of the two outermost elements is 76. The nitrate formed by the middle element is used to color fireworks in red.

To determine the elements and their positions in the periodic table, we need to find the atomic numbers that add up to 76. Let's consider the possibilities:

1. If the atomic numbers of the two outermost elements are consecutive, their sum cannot be 76 because the sum of two consecutive numbers is always odd. 2. If the atomic numbers of the two outermost elements have a difference of 2, their sum cannot be 76 because the sum of two consecutive even numbers is always even. 3. Therefore, the atomic numbers of the two outermost elements must have a difference of 4.

Let's find the possible combinations of atomic numbers that satisfy this condition:

- 36 and 40: The atomic numbers of the two outermost elements are 36 and 40, which add up to 76. The middle element would have an atomic number of 38. - 37 and 39: The atomic numbers of the two outermost elements are 37 and 39, which also add up to 76. The middle element would have an atomic number of 38.

Based on the information provided, the elements that belong to the same group in the periodic table are Krypton (Kr) with atomic number 36, Strontium (Sr) with atomic number 38, and Yttrium (Y) with atomic number 39.

Structure of the Atoms and Predicted Changes in Properties

The atoms of these elements have the following structures:

- Krypton (Kr): Krypton has an atomic number of 36, which means it has 36 protons and 36 electrons. Its electron configuration is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶. Krypton is a noble gas and has a full outer electron shell, making it chemically inert. - Strontium (Sr): Strontium has an atomic number of 38, which means it has 38 protons and 38 electrons. Its electron configuration is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s². Strontium is an alkaline earth metal and has two valence electrons in its outermost shell. - Yttrium (Y): Yttrium has an atomic number of 39, which means it has 39 protons and 39 electrons. Its electron configuration is 1s² 2s² 2p⁶ 3s² 3p⁶ 4s² 3d¹⁰ 4p⁶ 5s² 4d¹. Yttrium is a transition metal and has three valence electrons in its outermost shell.

With an increase in atomic mass, the properties of these elements can be predicted as follows:

- Krypton (Kr): As a noble gas, krypton is chemically inert and does not readily react with other elements. Increasing its atomic mass would not significantly affect its chemical properties. - Strontium (Sr): Alkaline earth metals become more reactive as you move down the group. Therefore, with an increase in atomic mass, strontium would become more reactive and have a stronger tendency to lose its two valence electrons to form positive ions. - Yttrium (Y): Transition metals generally exhibit similar chemical properties across a period. Therefore, with an increase in atomic mass, yttrium's chemical properties would remain relatively stable.

Natural Compounds of These Elements

Some natural compounds of these elements include:

- Krypton (Kr): Krypton is a noble gas and does not readily form compounds with other elements under normal conditions. However, it can form compounds with highly electronegative elements, such as fluorine and oxygen, under specific conditions. - Strontium (Sr): Strontium forms various compounds, including strontium oxide (SrO), strontium hydroxide (Sr(OH)₂), and strontium chloride (SrCl₂). Strontium compounds are often used in fireworks to produce red colors. - Yttrium (Y): Yttrium forms compounds such as yttrium oxide (Y₂O₃), yttrium chloride (YCl₃), and yttrium nitrate (Y(NO₃)₃). Yttrium compounds are used in various applications, including lasers, superconductors, and phosphors.

Please note that the information provided is based on the given context and may not cover all possible compounds or applications of these elements.