Question

The element phosphorus is located to the right of the element magnesium along the same period in the periodic table.

Which best describes the relationship of the elements?

Magnesium has a larger atomic number.
Phosphorus has a larger atomic mass.
Magnesium is in the same category as phosphorus.
Phosphorus has similar chemical properties as magnesium.

Answer 1

Phosphorus has a larger atomic mass.

Reason: Moving left to right across a period increases atomic number (Mg Z=12, P Z=15), and phosphorus also has the larger atomic mass (Mg ≈ 24.31 u, P ≈ 30.97 u).