Question

Question:Write the chemical formulas for the following compounds:
(a) Cesium sulfite
(b) Strontium thiocyanate
(c) Lithium hydride
(d) Sodium peroxide
(e) Ammonium dichromate
(f) Rubidium hydrogen sulfate

Short answer

1. The chemical formula for cesium sulfite is$C{s}_{2}S{O}_3$.
2. The chemical formula for strontium thiocyanate is$Sr{\left(SCN\right)}_2$.
3. The chemical formula for lithium hydride is$\text{LiH}$.
4. The chemical formula for sodium peroxide is$N{a}_2{O}_2$.
5. The chemical formula for ammonium dichromate is ${\left({\text{NH}}_{\text{4}}\right)}_{\text{2}}{\text{Cr}}_{\text{2}}{\text{O}}_{\text{7}}$.
6. The chemical formula for rubidium hydrogen sulfate is ${\text{RbHSO}}_{\text{4}}$.

Step-by-step solution

Step 1: Oxidation state

The most crucial thing is to correctly identify the charges (oxidation states) of the particles when writing formulae from systematic names. This will result in correct subscript numbers and charge balance.

Chemical formula for cesium sulfite

a)

The chemical formula is${\text{Cs}}_{\text{2}}{\text{SO}}_{\text{3}}$. Theions are the cesium cation (${\text{Cs}}^{\text{+}}$) and the sulfite anion ($\text{S}{{\text{O}}_{\text{3}}}^{\text{2}}$) from sulfurous acid.

Step 3: Chemical formula for strontium thiocyanate

b)

The ions are the strontium cation and the thiocyanate anion ${\text{SCN}}^{\text{-}}$. The chemical formula is ${\text{Sr(SCN)}}_{\text{2}}$.

Step 4: Chemical formula for Lithium hydride

c)

The ions are the lithium cation and the hydride anion. The chemical formula is $\text{LiH}$.

Step 5: Chemical formula for sodium peroxide

d)

The chemical formula is ${\text{Na}}_{\text{2}}{\text{O}}_{\text{2}}$. The ions are the sodium cation ,${\text{Na}}^{\text{+}}$ and the peroxide ion, ${{\text{O}}_{\text{2}}}^{\text{2}}$.

Step 6: Chemical formula for ammonium dichromate

e)

The chemical formula is ${\left({\text{NH}}_{\text{4}}\right)}_{\text{2}}{\text{Cr}}_{\text{2}}{\text{O}}_{\text{7}}$. The ion is the ammonium cation from the ammonia molecule, ${\text{NH}}_{\text{4}}^{\text{+}}$ and the dichromate anion,${\text{Cr}}_{\text{2}}{{\text{O}}_{\text{7}}}^{\text{2 -}}$.

Step 7: Chemical formula for rubidium hydrogen sulfate

f)

The chemical formula is ${\text{RbHSO}}_{\text{4}}$. The ions are the rubidium cation ${\text{Rb}}^{\text{+}}$, the hydrogen sulfate anion and the sulfuric acid deprotonation intermediate form.