Question

Write the formulas for the following compounds, and indicate the oxidation state of the group 14 element or of boron in each: (a) stannous fluoride, (b) germane, (c) diborane, (e) tin selenide, (d) tin(II) sulfate, (f) zinc carbonate.

Short answer

(a) Stannous fluoride: SnF2 (Sn oxidation state: +2) (b) Germane: GeH4 (Ge oxidation state: +4) (c) Diborane: B2H6 (B oxidation state: +3) (e) Tin selenide: SnSe (Sn oxidation state: +2) (d) Tin(II) sulfate: SnSO4 (Sn oxidation state: +2) (f) Zinc carbonate: ZnCO3 (C oxidation state: +4)

Step-by-step solution

(a) Stannous fluoride

Stannous fluoride is a compound containing tin (Sn) and fluoride (F). The term "stannous" indicates that tin has an oxidation state of +2. Therefore, Sn^2+ will combine with F^- to form the compound SnF2. The oxidation state of tin in this compound is +2.

(b) Germane

Germane is a compound containing germanium (Ge) and hydrogen (H). It is similar in structure to methane (CH4), but with germanium instead of carbon as the central atom. Each hydrogen atom has an oxidation state of -1, so germanium needs to have an oxidation state of +4 in order to balance the charges. The formula for this compound is GeH4.

(c) Diborane

Diborane is a compound containing boron (B) and hydrogen (H). The prefix "di" indicates that there are two boron atoms in the molecule. Each boron atom has an oxidation state of +3, and each hydrogen atom has an oxidation state of -1. The formula for diborane is B2H6.

(e) Tin selenide

Tin selenide is a compound containing tin (Sn) and selenium (Se). Selenium forms a selenide ion with a -2 charge (Se^(2-)), while tin can form ions with +2 or +4 oxidation states. Considering the +2 oxidation state for tin, we would have Sn^2+ and Se^(2-) ions. These ions combine in a 1:1 ratio, forming the compound SnSe. The oxidation state of tin in this compound is +2.

(d) Tin(II) sulfate

Tin(II) sulfate is a compound containing tin (Sn), sulfur (S), and oxygen (O). The (II) in the name indicates that tin has a +2 oxidation state. Sulfate is a polyatomic ion containing sulfur and oxygen with a -2 charge, represented as SO4^(2-). The tin ion (Sn^2+) combines with the sulfate ion (SO4^(2-)) to form the compound SnSO4. The oxidation state of tin in this compound is +2.

(f) Zinc carbonate

Zinc carbonate is a compound containing zinc (Zn), carbon (C), and oxygen (O). Zinc forms a +2 ion (Zn^2+), and carbonate is a polyatomic ion containing carbon and oxygen with a -2 charge, represented as CO3^(2-). The zinc ion (Zn^2+) combines with the carbonate ion (CO3^(2-)) to form the compound ZnCO3. The oxidation state of the carbon in this compound is +4.

Key concepts

Group 14 Elements

Group 14 elements are a fascinating family in the periodic table. They include carbon (C), silicon (Si), germanium (Ge), tin (Sn), and lead (Pb). These elements are known for their versatility in forming compounds.

• Carbon – One of the most important elements in life. It forms the backbone of organic chemistry, the study of life itself.
• Silicon – Widely used in electronics because of its semiconducting properties.
• Germanium – Less common, but also used in electronics and optics.
• Tin – Known for its use in alloys like bronze and solder.
• Lead – Historically used widely but now limited due to its toxicity.

One distinctive feature of Group 14 elements is their ability to form different oxidation states, usually +4 or +2. This flexibility allows them to take part in a variety of chemical reactions, forming numerous compounds. For example, in germane (GeH₄), germanium exists in the +4 oxidation state, while in some other compounds, it might exhibit a +2 oxidation state.

Chemical Formulas

Chemical formulas are essential for understanding chemistry, as they represent the composition of a compound. They indicate the elements involved and the number of atoms of each element in the compound. For example:

• In hydrogen peroxide, the formula is H₂O₂, showing two hydrogen atoms and two oxygen atoms.
• The formula for water is H₂O, which includes two hydrogen atoms and one oxygen atom.

The oxidation state is a crucial part of writing chemical formulas. It tells us about the charge of an atom in a compound, which is essential for balancing the formula. For instance, tin in stannous fluoride (SnF₂) has an oxidation state of +2, meaning it balances with two fluoride ions, each having a -1 charge.

Transition Metals

Transition metals are elements located in the middle of the periodic table. They are known for being good conductors of heat and electricity and for their ability to form various types of compounds through different oxidation states. Some examples include:

• Iron (Fe), known for forming rust (iron oxide) and used in construction materials.
• Copper (Cu), used in electrical wiring due to its excellent conductivity.
• Zinc (Zn), used in galvanization to prevent rust.

Transition metals can exhibit multiple oxidation states. This is due to their electronic structure, which allows electrons to be removed or shared with other atoms. Zinc, for example, typically has a +2 oxidation state as seen in zinc carbonate (ZnCO₃). The understanding of these states is crucial for predicting how metals will react and combine with other elements.

Polyatomic Ions

Polyatomic ions are groups of atoms that behave as a single unit with a specific charge. They are essential for creating complex compounds. Some common examples include:

• The sulfate ion, SO₄^2-, often found in salts like Epsom salt.
• The carbonate ion, CO₃^2-, found in minerals such as limestone.
• Nitrate ion, NO₃^-, commonly found in fertilizers.

These ions participate in chemical reactions similarly to single-atom ions. An understanding of polyatomic ions is important when naming compounds and writing formulas. For example, tin(II) sulfate (SnSO₄) includes the sulfate ion, balancing the +2 charge of tin with its own -2 charge. Knowing the formulas and charges of these ions helps in predicting the properties and reactions of the compounds they form.