Write the empirical (or molecular) formulas of compounds that these elements in the third period are expected to form with molecular oxygen and molecular chlorine. (if different oxidation states are possible for an element, write the formula for a highest oxidation state.) in each case indicate whether you expect the compound to be ionic or molecular.

Na₂O₂ (Ionic)

MgO (Ionic)

Al₂O₂ (Ionic)

SiO₂ (Molecular)

PO₂ (Molecular)

SO (Molecular)

Cl₂O (Molecular)

NaCl (Ionic)

MgCl₂ (Ionic)

AlCl (Ionic)

SiCl₂ (Molecular)

PCl₂ (Molecular)

SCl (Molecular)

Cl₃⁻ (Molecular)

Explanation:

The elements of the third period are sodium (Na), magnesium (Mg), aluminum (Al), silicon (Si), phosphorus (P), sulfur (S), chlorine (Cl), and argon (Ar). The reactions of the metals with nonmetal will make an ionic compound, and the reactions between nonmetals, a molecular compound.

The metals are Na, Mg, and Al. Oxygen and Chlorine are nonmetals.

The reactions with molecular oxygen (O₂) will be:

2Na + O₂ → Na₂O₂ (Ionic)

2Mg + O₂ → 2MgO (Ionic)

2Al + O₂ → Al₂O₂ (Ionic)

Si + O₂ → SiO₂ (Molecular)

P + O₂ → PO₂ (Molecular)

2S + O₂ → 2SO (Molecular)

4Cl + O₂ → 2Cl₂O (Molecular)

Ar + O₂ → NOT REACT (Ar is a noble gas)

The reactions with molecular chlorine (Cl₂) will be:

2Na + Cl₂ → 2NaCl (Ionic)

Mg + Cl₂ → MgCl₂ (Ionic)

2Al + Cl₂ → 2AlCl (Ionic)

Si + Cl₂ → SiCl₂ (Molecular)

P + Cl₂ → PCl₂ (Molecular)

2S + Cl₂ → 2SCl (Molecular)

Cl + Cl₂ → Cl₃⁻ (Molecular)

Ar + Cl₂ → NOT REACT

the ideal gas law equation is as follows

pv = nrt

where p - pressure

v - volume

n - number of moles

r - universal gas constant

t - temperature

so if the pressure, volume and temperature are already known

we are left with n and r

since r is the universal gas constant that has a known fixed value then r too is known

so we are left with 'n'

once we know temperature volume and pressure

we can find the number of moles of gas present using the ideal gas law equation

this is not my own answer, this is an answer for the same question by the user blahblahmali. i do not claim ownership of this account.