Question

Identify the element that belongs to 2nd group and 3rd period.

• A. Na
• B. Al
• C. Mg
• D. Cl

Answer 1

The Correct Option is C

To determine the element that belongs to the 2nd group and 3rd period, we need to understand the organization of the periodic table. The periodic table is arranged in periods (horizontal rows) and groups (vertical columns).

• Periods: The 3rd period includes elements in the third row of the periodic table. These elements have their outermost electrons in the third energy level.
• Groups: The 2nd group, also known as Group 2 or the alkaline earth metals, consists of elements that have two electrons in their outermost shell.

Let's analyze the given options:

• Na (Sodium): Located in the 3rd period but in the 1st group, which contains alkali metals with one electron in their outermost shell.
• Al (Aluminum): Located in the 3rd period but in the 13th group, with elements from group 13 having three electrons in their outermost shell.
• Mg (Magnesium): Located in the 3rd period and the 2nd group, fitting the criteria of having two electrons in their outer shell.
• Cl (Chlorine): Located in the 3rd period but in the 17th group, with elements from group 17 having seven electrons in their outermost shell.

Based on this analysis, the correct element that belongs to the 2nd group and 3rd period is Mg (Magnesium).

Answer 2

Correct answer: Mg 

Explanation:
The periodic table is organized into groups (vertical columns) and periods (horizontal rows).

– The 2nd group is also known as the alkaline earth metals group.
– The 3rd period includes the elements with atomic numbers 11 to 18.

Let's check the options:
• Na (Sodium) – Group 1, Period 3
• Al (Aluminium) – Group 13, Period 3
• Mg (Magnesium) – Group 2, Period 3 ← Correct
• Cl (Chlorine) – Group 17, Period 3

So, the element that belongs to the 2nd group and 3rd period is Magnesium (Mg).