Nthe third period of the periodic table, sodium is followed by magnesium, aluminum, silicon, and phosphorus. which of these elements has the smallest atomic size? sodium magnesium aluminum silicon phosphorus

Option (5) is the correct answer.

Explanation:

When we move from left to right across a period in a periodic table then there will occur a decrease in size of the atoms because electrons add to the same shell.

As a result, nucleus tends to pull the electrons towards itself due to which shrinkage in the size of atoms tends to occur.

Sodium is placed at the extreme left of row 3 and phosphorous is placed at the right side of row 3.

This means atomic size is decreasing from sodium to phosphorous.

Thus, we can conclude that out of the given options phosphorus element has the smallest atomic size.

1. for the first question, we must find the mass of the anhydrous salt, mgso₄. the molar mass for mgso₄·7h₂o is 246.47 g/mol, while that of mgso₄ is 120.37 g/mol.7.834 g mgso₄·7h₂o * 1 mol mgso₄·7h₂o/246.47 g * 1 mol mgso₄/1 mol mgso₄·7h₂o * 20.37 g mgso₄/mol = 0.647 g mgso₄

2. mass of water = mass of sample - mass of anhydrous salemass of water = 7.834 - 0.647 = 7.19 gpercent water in hydrate = 7.19/7.834 * 100 = 91.74%