To determine which element is the least similar to magnesium (Mg) among the given options, we need to consider the periodic table and the groups in which these elements are found.
1. Understanding Groupings:
- Magnesium (Mg) is an element in Group 2 of the periodic table, also known as the alkaline earth metals.
- The elements in Group 2 include Beryllium (Be), Magnesium (Mg), Calcium (Ca), Strontium (Sr), Barium (Ba), and Radium (Ra).
2. Evaluating Given Options:
- Option A: Sodium (Na): Sodium is in Group 1 of the periodic table, known as the alkali metals.
- Option B: Strontium (Sr): Strontium is also in Group 2, just like Magnesium.
- Option C: Beryllium (Be): Beryllium is in Group 2, similar to Magnesium.
- Option D: Calcium (Ca): Calcium is another Group 2 element.
3. Comparing Properties:
- Elements within the same group have similar properties due to their identical valence electron configuration.
- Magnesium is in Group 2, so we look for the element in the options that is the farthest from this group. The alkali metals (Group 1), which include Sodium (Na), have different properties compared to the alkaline earth metals.
From the evaluation above:
- Sodium (Na) is in Group 1
- Strontium (Sr), Beryllium (Be), and Calcium (Ca) are in Group 2
Conclusion:
The element that is least similar to Magnesium (Mg) due to being in a different group (Group 1 vs. Group 2) is Sodium (Na).
Therefore, the least similar element to magnesium is:
A. Na
The correct answer is 1.
