Question

Write formulas for the compounds: (a) magnesium perchlorate; (b) lead(II) acetate; (c) tin(IV) oxide; (d) hydroiodic acid; (e) chlorous acid; (f) sodium hydrogen sulfite; (g) calcium dihydrogen phosphate; (h) aluminum phosphate; (i) dinitrogen tetroxide; (j) disulfur dichloride.

Short answer

The formulas for the compounds are: (a) Mg(ClO4)2; (b) Pb(C2H3O2)2; (c) SnO2; (d) HI; (e) HClO2; (f) NaHSO3; (g) Ca(H2PO4)2; (h) AlPO4; (i) N2O4; (j) S2Cl2.

Step-by-step solution

Finding the formula for Magnesium perchlorate

Magnesium is a metal and perchlorate is a polyatomic ion. This makes Magnesium perchlorate an ionic compound. Magnesium has a +2 charge and perchlorate has a -1 charge. Balancing the charges gives Mg(ClO4)2.

Finding the formula for Lead(II) acetate

Lead(II) indicates that Lead has a +2 charge. Acetate is a polyatomic ion with a -1 charge. Balancing the charges gives Pb(C2H3O2)2.

Finding the formula for Tin(IV) oxide

Tin(IV) means Tin has a +4 charge. Oxide has a -2 charge. Balancing the charges gives SnO2.

Finding the formula for Hydroiodic acid

In acids, the 'hydro' prefix indicates that it is a binary acid, and the 'ic' suffix indicates that it has more oxygen atoms. Hydroiodic acid becomes HI.

Finding the formula for Chlorous acid

The root 'chlor' indicates that Chlorine is involved, and the 'ous' suffix indicates that it has fewer oxygen atoms. Chlorous Acid is HClO2.

Finding the formula for Sodium hydrogen sulfite

Sodium has a +1 charge, and Hydrogen sulfite (HSO3) has a -1 charge. Balancing the charges gives NaHSO3.

Finding the formula for Calcium dihydrogen phosphate

Calcium has a +2 charge and Dihydrogen phosphate (H2PO4) has a -1 charge. Balancing the charges gives Ca(H2PO4)2.

Finding the formula for Aluminum phosphate

Aluminum has a +3 charge, and Phosphate has a -3 charge. Balancing the charges gives AlPO4.

Finding the formula for Dinitrogen tetroxide

In molecular compounds, prefixes indicate the number of atoms. So, 'di' stands for 2 and 'tetra' stands for 4. Therefore, Dinitrogen tetroxide becomes N2O4.

Finding the formula for Disulfur dichloride

In molecular compounds, prefixes indicate the number of atoms. So, 'di' stands for 2. Therefore, Disulfur dichloride becomes S2Cl2.

Key concepts

ionic compounds

Ionic compounds are formed when metals transfer electrons to non-metals, leading to the creation of ions. These ions, with opposite charges, attract each other and form a stable compound. For instance, magnesium perchlorate is an ionic compound. Magnesium, a metal, donates two electrons to achieve a full octet, forming a cation (Mg^{2+}).
Perchlorate ( ext{ClO}_4^-), a polyatomic ion, accepts these electrons, balancing out the charges. To write the chemical formula for an ionic compound, identify the metal's charge and the non-metal or polyatomic ion's charge, then adjust the quantities so that the overall charge is neutral.
For magnesium perchlorate, it's Mg(ClO_4)_2, showing the need for two perchlorate ions to balance the +2 charge of magnesium.

molecular compounds

Molecular compounds emerge when two non-metals share electrons, establishing covalent bonds. These compounds are distinct from ionic compounds since they do not form ions. Instead, molecular compounds involve atoms bound by shared electron pairs.
Prefixes in molecular compound names such as "di" and "tetra" are crucial because they indicate the number of atoms of each element present in the compound. For example, in dinitrogen tetroxide (N2O4), "di" signifies two nitrogen atoms, while "tetra" refers to four oxygen atoms.
Understanding the prefixes is essential for deciphering the molecular formula accurately, making these compounds unique in their naming and structural composition.

polyatomic ions

Polyatomic ions are charged entities comprising multiple atoms covalently bonded together. Rather than a single atom gaining or losing electrons, a cluster of atoms works collectively to form an ion.
These ions play a significant role in forming ionic compounds, acting as the organized non-metal part. For instance, the acetate ion, C2H3O2^-, is a polyatomic ion involved in forming lead(II) acetate, Pb(C2H3O2)2. Here, the acetate ion maintains its form while participating in ionic bonding.
Being aware of common polyatomic ions and their charges is crucial, as they frequently appear across various chemical reactions and compounds, simplifying the process of writing and balancing chemical formulas.

chemical formulas

Chemical formulas are scientific shorthand used to represent chemical compounds. They express the types and numbers of atoms composing a molecule or compound succinctly.
In ionic compounds, this involves balancing the charges of the ions involved to produce a neutral compound. For instance, calcium dihydrogen phosphate, Ca(H2PO4)2, reflects this approach with two dihydrogen phosphate ions balancing the charge of one calcium ion.
For molecular compounds, the chemical formula directly reflects the quantity of each atom present, denoted by the prefixes in their names. Hence, disulfur dichloride becomes S2Cl2, with "di" affecting both sulfur and chlorine.
Mastering chemical formulas requires understanding both ionic and covalent bonding principles, along with recognizing certain naming conventions and common polyatomic ions.