Based on their locations in the periodic table, which two elements are most likely to form covalent bonds with each other?

magnesium (Mg) and sulfur (S)

sodium (Na) and bromine (Br)

potassium (K) and iodine (I)

nitrogen (N) and oxygen (O)

Nitrogen (N) and Oxygen (O)

Explanation:

Nitrogen (N) has five valence electrons, so it needs three more valence electrons to complete its octet. Two nitrogen atoms will combine. Each will share three electrons to form three covalent bonds, i.e., a triple bond, resulting in a nitrogen molecule.

The valency of oxygen (O) is two, which means that it requires two electrons to complete its outermost (valence) shell. Therefore, two oxygen atoms will combine and share their two valence electrons, resulting in a double bond.

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%

there are two significant figures.