Question

fill in the missing words
out of the following five elements, calcium, sodium, chlorine, phosphorus, magnesium, □ has the lowest atomic weight and □ has
the highest atomic weight.

Explanation:

Step1: Recall atomic weights

Atomic weights (approximate): Sodium ($\text{Na}$) ≈ 23, Magnesium ($\text{Mg}$) ≈ 24, Phosphorus ($\text{P}$) ≈ 31, Chlorine ($\text{Cl}$) ≈ 35.5, Calcium ($\text{Ca}$) ≈ 40.

Step2: Identify lowest and highest

From the values, sodium has the lowest atomic weight. Calcium has the highest atomic weight among the given elements.

Answer:

First blank: sodium; Second blank: calcium