Question

Which of the following statement is false? (1) The group in which all the elements do not have same number of valence electrons is zero. (2) Elements of II period elements are collectively called as bridge elements. (3) The cause of periodicity of properties is reoccurrence of similar outer electronic configuration. (4) The most reactive gaseous element in the second period is oxygen.

Short answer

The most reactive gaseous element in the second period is fluorine, not oxygen.

Step-by-step solution

- Understanding Group Properties

First, recall that a group in the periodic table consists of elements with the same number of valence electrons. Therefore, the statement about group zero must refer to the noble gases.

- Analyzing Bridge Elements

Consider the II period elements in the periodic table, which includes elements like Li, Be, B, C, N, O, F, and Ne. These elements are not generally referred to as 'bridge elements.'

- Cause of Periodicity

Understand that the periodicity of properties is due to the reoccurrence of similar outer electronic configurations. This can be seen across every period in the periodic table.

- Most Reactive Gaseous Element in Second Period

In the second period, the most reactive gaseous element is fluorine, not oxygen. Fluorine is more reactive due to its high electronegativity and ability to accept electrons easily.

Conclusion

Based on the analysis of each statement, determine the false statement accurately. The false statement among the given options is related to the reactivity of elements in the second period.

Key concepts

valence electrons

Valence electrons are the outermost electrons of an atom. They are found in the highest energy level of an atom and play a crucial role in chemical bonding. These electrons determine the chemical properties of an element.

Understanding the number of valence electrons helps us predict how elements will react with each other.

• For example, elements in Group 1 have one valence electron, making them highly reactive because they seek to lose one electron to achieve a stable configuration.
• In contrast, Group 18 elements (noble gases) have a full set of valence electrons, making them very stable and unreactive.

So when analyzing groups in the periodic table, remember the similarity in valence electrons is what makes the elements in a group chemically similar.

bridge elements

Bridge elements, also referred to as diagonal relationships, are elements that show similarities to elements in the adjacent main group of the following period. This usually occurs between the elements of periods 2 and 3. For instance, lithium (Li) in Group 1 is similar to magnesium (Mg) in Group 2, despite being different groups. However, it is crucial to note that elements of the second period, like Li, Be, B, C, N, O, F, and Ne, are not called bridge elements. Instead, specific cross-period similarities are observed.

• Lithium (Li) and Magnesium (Mg).
• Beryllium (Be) and Aluminium (Al).

These similarities are due to similar atomic sizes and some overlap in chemical properties.

periodicity

Periodicity refers to the recurring trends in the properties of elements across different periods (horizontal rows) and groups (vertical columns) of the periodic table. Such properties repeat at regular intervals when elements are arranged by increasing atomic number. The primary reason behind periodicity is the reoccurrence of similar outer electronic configurations at regular intervals.

Consider how the elements in each group show similar reactivity due to their similar valence electron configurations:

• Group 1 elements (alkali metals) are highly reactive because they all have one valence electron.
• Group 17 elements (halogens) are very reactive non-metals due to having seven valence electrons.

By recognizing the periodic trends, you can predict the chemical properties and reactivities of elements from their position in the periodic table.

reactivity

Reactivity is the tendency of a substance to engage in chemical reactions. This depends largely on the arrangement of valence electrons and the energy required to either gain, lose, or share these electrons.

In the periodic table, reactivity follows a predictable pattern:

• Within a group, reactivity in metals increases as you move down the group (e.g., alkali metals like sodium and potassium become more reactive).
• For non-metals, reactivity typically decreases down a group (e.g., halogens like fluorine are more reactive than iodine).

Comparing elements within the same period, fluorine (F) is the most reactive element in the second period. This is due to its high electronegativity and small atomic radius that allows it to attract electrons very strongly. Therefore, the statement 'the most reactive gaseous element in the second period is oxygen' is incorrect, because fluorine is actually the most reactive.