Question

write the correct formula for each molecular compound.

1. disulfur decafluoride
2. dihydrogen monosulfide
3. nitrogen trihydride
4. phosphorus trichloride

name the following molecular compounds.

1. cf₄
2. so₃
3. p₂o₅
4. sf₆

write the correct formula for each ionic compound.

1. aluminum sulfate
2. lithium nitrate
3. cesium oxide
4. potassium phosphide
5. ammonium chloride
6. iron (ii) acetate
7. scandium sulfide
8. copper (ii) hydroxide
9. calcium phosphate
10. tin (ii) sulfite

name the following ionic compounds.

1. ba(no₃)₂
2. sncl₄

Explanation:

Step1: Write molecular compound formulas

For disulfur decafluoride, "di -" means 2 sulfur atoms and "deca -" means 10 fluorine atoms, so the formula is $S_2F_{10}$.
For dihydrogen monosulfide, "di -" means 2 hydrogen atoms and "mono -" means 1 sulfur atom, so the formula is $H_2S$.
For nitrogen trihydride, "tri -" means 3 hydrogen atoms with 1 nitrogen atom, so the formula is $NH_3$.
For phosphorus trichloride, "tri -" means 3 chlorine atoms with 1 phosphorus atom, so the formula is $PCl_3$.

Step2: Name molecular compounds

$CF_4$: Carbon is the first element and there is 1 carbon atom. "Tetra -" for 4 fluorine atoms, so it is carbon tetrafluoride.
$SO_3$: Sulfur is the first element and there is 1 sulfur atom. "Tri -" for 3 oxygen atoms, so it is sulfur trioxide.
$P_2O_5$: There are 2 phosphorus atoms, so we use "di -", and 5 oxygen atoms, so "penta -", so it is diphosphorus pentoxide.
$SF_6$: There is 1 sulfur atom and "hexa -" for 6 fluorine atoms, so it is sulfur hexafluoride.

Step3: Write ionic compound formulas

For aluminum sulfate, aluminum has a +3 charge ($Al^{3 + }$) and sulfate has a - 2 charge ($SO_4^{2-}$). To balance the charges, we need 2 aluminum ions and 3 sulfate ions, so the formula is $Al_2(SO_4)_3$.
For lithium nitrate, lithium has a +1 charge ($Li^+$) and nitrate has a - 1 charge ($NO_3^-$), so the formula is $LiNO_3$.
For cesium oxide, cesium has a +1 charge ($Cs^+$) and oxygen has a - 2 charge ($O^{2 - }$), so we need 2 cesium ions, and the formula is $Cs_2O$.
For potassium phosphide, potassium has a +1 charge ($K^+$) and phosphorus has a - 3 charge ($P^{3 - }$), so we need 3 potassium ions, and the formula is $K_3P$.
For ammonium chloride, ammonium has a +1 charge ($NH_4^+$) and chloride has a - 1 charge ($Cl^-$), so the formula is $NH_4Cl$.
For iron (II) acetate, iron has a +2 charge ($Fe^{2+}$) and acetate has a - 1 charge ($C_2H_3O_2^-$), so we need 2 acetate ions, and the formula is $Fe(C_2H_3O_2)_2$.
For scandium sulfide, scandium has a +3 charge ($Sc^{3+}$) and sulfur has a - 2 charge ($S^{2 - }$), so we need 2 scandium ions and 3 sulfur ions, and the formula is $Sc_2S_3$.
For copper (II) hydroxide, copper has a +2 charge ($Cu^{2+}$) and hydroxide has a - 1 charge ($OH^-$), so we need 2 hydroxide ions, and the formula is $Cu(OH)_2$.
For calcium phosphate, calcium has a +2 charge ($Ca^{2+}$) and phosphate has a - 3 charge ($PO_4^{3 - }$), so we need 3 calcium ions and 2 phosphate ions, and the formula is $Ca_3(PO_4)_2$.
For tin (II) sulfite, tin has a +2 charge ($Sn^{2+}$) and sulfite has a - 2 charge ($SO_3^{2 - }$), so the formula is $SnSO_3$.

Step4: Name ionic compounds

For $Ba(NO_3)_2$, barium is the metal and nitrate is the poly - atomic ion, so it is barium nitrate.
For $SnCl_4$, tin has a +4 charge here (since there are 4 chloride ions each with a - 1 charge), so it is tin (IV) chloride.

Answer:

1. Molecular compound formulas:

• disulfur decafluoride: $S_2F_{10}$
• dihydrogen monosulfide: $H_2S$
• nitrogen trihydride: $NH_3$
• phosphorus trichloride: $PCl_3$

1. Molecular compound names:

• $CF_4$: carbon tetrafluoride
• $SO_3$: sulfur trioxide
• $P_2O_5$: diphosphorus pentoxide
• $SF_6$: sulfur hexafluoride

1. Ionic compound formulas:

• aluminum sulfate: $Al_2(SO_4)_3$
• lithium nitrate: $LiNO_3$
• cesium oxide: $Cs_2O$
• potassium phosphide: $K_3P$
• ammonium chloride: $NH_4Cl$
• iron (II) acetate: $Fe(C_2H_3O_2)_2$
• scandium sulfide: $Sc_2S_3$
• copper (II) hydroxide: $Cu(OH)_2$
• calcium phosphate: $Ca_3(PO_4)_2$
• tin (II) sulfite: $SnSO_3$

1. Ionic compound names:

• $Ba(NO_3)_2$: barium nitrate
• $SnCl_4$: tin (IV) chloride