Which of the following definitions is related to the modern periodic table?
A) A group is a horizontal row on the periodic table.
B) A period is a column on the periodic table.
C) The elements in each group have similar chemical properties.
D) The B groups contain the representative elements.
E) The A groups contain the transition elements.
The correct answer and explanation is :
The correct answer is C) The elements in each group have similar chemical properties.
Explanation:
The modern periodic table is organized based on the periodic law, which states that the properties of elements repeat periodically when arranged by increasing atomic number. The table is divided into periods (horizontal rows) and groups (vertical columns). Here’s a breakdown of the other options:
- A) A group is a horizontal row on the periodic table.
This is incorrect. A group refers to a vertical column on the periodic table, not a horizontal row. Horizontal rows are called periods. - B) A period is a column on the periodic table.
This is also incorrect. A period is a horizontal row, while a group refers to a column. Elements within the same period have the same number of electron shells but differ in their chemical properties. - C) The elements in each group have similar chemical properties.
This is the correct answer. Elements within the same group (or column) of the periodic table have similar chemical properties due to having the same number of valence electrons. This similarity in electron configuration leads to predictable behavior in chemical reactions. For example, alkali metals (Group 1) are all highly reactive and share similar properties, such as being good conductors of heat and electricity. - D) The B groups contain the representative elements.
This is incorrect. The representative elements are the elements in Groups 1, 2, and 13-18 (also called the A groups). The B groups refer to the transition elements (Groups 3-12), which are typically metals with distinct properties, including the ability to form multiple oxidation states. - E) The A groups contain the transition elements.
This is also incorrect. The A groups contain the representative elements, while the transition elements are found in the B groups.
In summary, the periodic table’s structure shows a repeating pattern of chemical properties for elements, especially within the same group.