Problem 37 - Chemistry and Chemical Reactivity

Question

Give the symbol, including the correct charge, for each of the following ions: (a) barium ion (b) titanium(IV) ion (c) phosphate ion (d) hydrogen carbonate ion (e) sulfide ion (f) perchlorate ion (g) cobalt(II) ion (h) sulfate ion

Step-by-Step Solution

Answer

(a) Ba²⁺, (b) Ti⁴⁺, (c) PO₄³⁻, (d) HCO₃⁻, (e) S²⁻, (f) ClO₄⁻, (g) Co²⁺, (h) SO₄²⁻.

Step 1: Identify the Element Symbols

First, recognize the symbols for each of the given elements or radicals. For example, barium has the symbol Ba, titanium has Ti, phosphate is a polyatomic ion with PO₄, hydrogen carbonate is HCO₃, sulfur for sulfide is S, perchlorate is ClO₄, cobalt is Co, and sulfate is another polyatomic ion SO₄.

Step 2: Determine the Charge of Each Ion

Next, identify the charge associated with each ion: (a) The barium ion (Ba) has a charge of +2. (b) Titanium(IV) indicates titanium ion with a +4 charge (Ti⁴⁺). (c) Phosphate ion (PO₄) typically has a -3 charge. (d) Hydrogen carbonate ion (HCO₃) has a -1 charge. (e) Sulfide ion (S) is commonly found to have a -2 charge. (f) Perchlorate ion (ClO₄) has a -1 charge. (g) Cobalt(II) ion implies a +2 charge (Co²⁺). (h) Sulfate ion (SO₄) generally has a -2 charge.

Step 3: Combine Symbols with Charges

For each ion, combine the element or polyatomic ion symbol with its respective charge denoted as a superscript: (a) Ba²⁺, (b) Ti⁴⁺, (c) PO₄³⁻, (d) HCO₃⁻, (e) S²⁻, (f) ClO₄⁻, (g) Co²⁺, (h) SO₄²⁻.

Key Concepts

Element Symbols

Chemical elements are the basic building blocks of matter and each element is represented by a unique symbol. These symbols are usually one or two letters, with the first letter capitalized:

• Barium is represented by Ba
• Titanium is represented by Ti
• Cobalt is represented by Co

For polyatomic ions, which are clusters of atoms that carry a charge, we use the formula representing the specific group of elements bonded together:

• Phosphate is written as PO₄
• Hydrogen carbonate as HCO₃
• Sulfate as SO₄

These symbols allow chemists to precisely identify and distinguish between different elements and compounds.

Ion Charges

Ions are atoms or molecules that have gained or lost electrons, giving them a charge. You can identify ion charges by knowing the valence electrons shared or lost:

• Barium (Ba²⁺) loses two electrons resulting in a +2 charge.
• Titanium(IV) (Ti⁴⁺) suggests it loses four electrons resulting in a +4 charge.
• Phosphate (PO₄³⁻) typically gains three electrons, giving it a -3 charge.
• Hydrogen carbonate (HCO₃⁻) gains one electron with a -1 charge.
• Sulfide (S²⁻) gains two electrons resulting in a -2 charge.
• Perchlorate (ClO₄⁻) and sulfate (SO₄²⁻) also have negative charges by gaining electrons.
• Cobalt(II) (Co²⁺) loses two electrons resulting in a +2 charge.

Prescribing positive or negative signs to ions is crucial for understanding chemical reactions and bonding behavior.

Polyatomic Ions

Polyatomic ions are ions composed of two or more atoms bonded together, acting as a single charged entity. These entities often involve complex bonding and sharing of electrons:

• Phosphate (PO₄³⁻) consists of phosphorous and four oxygen atoms collectively carrying a -3 charge.
• Hydrogen carbonate (HCO₃⁻) comprises hydrogen, carbon, and three oxygen atoms with a -1 charge.
• Sulfate (SO₄²⁻) includes sulfur and four oxygen atoms resulting in a -2 charge.
• Perchlorate (ClO₄⁻) has one chlorine atom bonded to four oxygen atoms with a -1 charge.

These ions are essential to numerous chemical processes and reactions, making understanding them integral to chemistry.

Chemical Notation

Chemical notation is a shorthand method chemists use to convey detailed information about chemical compounds with symbols and numerals. The notations include:

• Element symbols (like Ba for Barium or Ti for Titanium) associated with specific elements.
• Superscripts indicate the charge of ions, such as Ba²⁺ or PO₄³⁻.
• Subscripts in chemical formulas show the number of each type of atom in a compound, such as the 4 in ClO₄⁻.

Chemical notations provide all necessary data for understanding the makeup and charge of molecules, ensuring that students comprehend complex concepts quickly and accurately.