The reactivity depends on the elements valence electrons. The need to be stable will make an element become more reactive, In order for an atom to be stable, it needs 8 valence electrons in its outer shell.
Since Calcium is in group 2, it has 2 valence electrons, and would rather give up the electrons. While Sulfur has 6, it would need to gain 2 more to be stable, making it more reactive.
Answer: The answer might be A or B.
Explanation:
Algebraic expression: It is an expression which is frame from the variables (x,y etc.), integer constants and algebraic operations (+,- , multiplication and division etc.).
Sequence is defined as the structured list of numbers.
Now, according to the given sequence, first place is , second is , third is , fourth is . Thus, place of the sequence should be determined.
The place of the sequence is . Therefore, option (A) is correct.