Formulae Of Ionic Compounds & Their Names - Part 1 | Properties of Matter | Chemistry | FuseSchool

Summary

This educational script introduces the formation and nomenclature of ionic compounds. It demonstrates the process of writing and naming formulas for ionic compounds through examples, such as NaCl (sodium chloride) and MgO (magnesium oxide). The script emphasizes the importance of balancing charges in ionic compounds, as seen in CaF2 (calcium fluoride) and Al2S3 (aluminum sulfide), and provides a step-by-step guide to deducing the formula and name of ionic compounds from their constituent ions.

Takeaways

• 🧪 Ionic bonds are the electrostatic attraction between oppositely charged ions.
• 🔋 Na+ ion is formed when sodium loses one electron, which is then transferred to a Cl atom to form Cl-.
• ✍️ To write the formula for an ionic compound, write the ions side by side with their charges in superscript, then criss-cross the charges to form subscripts.
• 🔄 The resulting formula for sodium chloride is NaCl, where the positive metal ion (Na) comes first, followed by the negative non-metal ion (Cl).
• 📚 The naming rule for ionic compounds: for non-metal ions, the first syllable stays the same, but the ending changes to '-ide'.
• 🧊 Chlorine becomes chloride in NaCl, so the compound is called sodium chloride.
• 🧲 Another example: Mg2+ and O2- ions criss-cross to form MgO, called magnesium oxide.
• 🔍 When deducing the formula of ionic compounds, reduce the subscripts if possible, like Mg2O2 to MgO.
• 🧮 For Ca2+ and F- ions, the correct formula is CaF2, called calcium fluoride, balancing the charges by ensuring neutrality.
• 🔬 The formula for aluminum sulfide from Al3+ and S2- ions is Al2S3, maintaining the neutral charge of the compound.

Q & A

What is an ionic bond?

An ionic bond is the electrostatic attraction between oppositely charged ions, typically formed when one atom loses an electron to become a positive ion, and another atom gains that electron to become a negative ion.

How is the formula for an ionic compound determined?

The formula for an ionic compound is determined by criss-crossing the charges of the ions involved, bringing them down to subscripts, and reducing them if necessary to reflect the simplest ratio of ions that results in a neutral charge overall.

What is the correct formula for the ionic compound formed between sodium (Na) and chlorine (Cl)?

The correct formula is NaCl. Sodium (Na+) and chlorine (Cl-) combine in a 1:1 ratio to form sodium chloride.

How is the name of an ionic compound typically structured?

The name of an ionic compound starts with the positive metal ion, followed by the negative non-metal ion, whose name is modified by dropping the ending and replacing it with '-ide'.

What is the name of the compound with the formula MgO?

The name of the compound with the formula MgO is magnesium oxide. The 'ox' syllable from oxygen is kept, and the ending is replaced with '-ide'.

Why is the formula for MgO written as MgO instead of Mg2O2?

The formula Mg2O2 is reduced to MgO because the ratio of magnesium ions (Mg2+) to oxygen ions (O2-) is 1:1, which simplifies to the formula MgO.

What is the formula and name for the ionic compound formed between calcium (Ca) and fluorine (F)?

The formula is CaF2, and the name of the compound is calcium fluoride. Calcium (Ca2+) bonds with two fluorine ions (F-) to balance the charges.

Why is it important for ionic compounds to have a neutral overall charge?

Ionic compounds must have a neutral overall charge to maintain stability. This means that the total positive charge must balance the total negative charge in the compound.

What is the formula and name for the ionic compound formed between aluminum (Al) and sulfur (S)?

The formula is Al2S3, and the name of the compound is aluminum sulfide. Aluminum (Al3+) bonds with sulfur (S2-) in a 2:3 ratio to balance the charges.

What happens to the charge numbers when writing the formula of an ionic compound?

The charge numbers of the ions are criss-crossed and brought down as subscripts in the formula. If possible, the subscripts are simplified to the lowest whole number ratio, which ensures the formula reflects the simplest ratio of ions that maintains a neutral overall charge.