CHEMICAL BONDS

Chemical bonds are forces that hold atoms together to form compounds. When atoms join, they do this through different types of bonds depending on the electrons involved. The main types are ionic bonds, where electrons transfer from one atom to another; covalent bonds, where atoms share electrons; and metallic bonds found in metals.

Think of salt (sodium chloride) commonly used in Nigerian kitchens. The sodium atom gives its electron to chlorine, creating an ionic bond that holds them together as one compound. In another example, water molecules form through covalent bonds where hydrogen and oxygen share electrons.

Understanding these bonds helps explain why substances behave the way they do. Strong bonds mean high melting points, while weak bonds produce low melting points. This knowledge is crucial for predicting chemical reactions and compound properties.

An ionic bond forms when atoms transfer electrons from one to another. Typically, a metal atom loses electrons to become positive (cation), while a non-metal gains those electrons to become negative (anion). These oppositely charged ions attract each other powerfully, creating an ionic compound.

Think about table salt, which every Nigerian kitchen has. Sodium metal loses one electron to chlorine gas, forming Na⁺ and Cl⁻ ions. These ions bond together to make sodium chloride (NaCl), the salt we use daily. The ionic bond between them is very strong.

Ionic compounds have predictable properties: they're solid at room temperature, dissolve in water, conduct electricity when melted or dissolved, and have high melting points. Understanding electron transfer is crucial for predicting which elements form ionic bonds together.

Ionic compounds form when atoms transfer electrons completely to each other, creating charged particles called ions. These compounds have fascinating properties worth understanding for your WAEC exam.

Ionic compounds are usually solids at room temperature with very high melting and boiling points because the ions are held together by strong electrostatic forces. Common salt, sodium chloride, which you use in your Nigerian kitchen, is a perfect example. It melts only at 801°C! These compounds conduct electricity when melted or dissolved in water because the ions become free to move. They're also generally brittle—they shatter rather than bend—and most dissolve well in polar solvents like water.

These properties directly result from the strong ionic bonds holding the structure together. When you heat or apply pressure, these rigid structures break suddenly instead of deforming.

When two elements form an ionic bond, naming the compound is straightforward. The metal (positive ion) comes first, followed by the non-metal (negative ion) whose name changes to end in "-ide." For example, sodium chloride forms when sodium metal bonds with chlorine gas—this is common table salt you use at home in Nigeria.

When the non-metal is part of a group like oxygen (forming oxides), sulphur (forming sulphides), or nitrogen (forming nitrides), you simply add these endings. If a metal can form more than one ion, like iron making both Fe²⁺ and Fe³⁺, you add Roman numerals in brackets: iron(II) oxide and iron(III) oxide respectively.

Practice naming by identifying the metal first, then apply the "-ide" rule to the non-metal.

A covalent bond forms when two atoms share electrons in their outermost shells. This sharing happens because both atoms want to achieve a stable electron arrangement, usually like the noble gases. When atoms share electrons fairly equally, the bond is nonpolar covalent, but when one atom pulls electrons more strongly, it becomes polar covalent.

Think of cooking with palm oil and water at home—they don't mix because water molecules form strong covalent bonds internally. Water itself (H₂O) is a perfect example: each hydrogen atom shares electrons with oxygen, creating two covalent bonds that hold the molecule together strongly.

Covalent compounds have low melting points, don't conduct electricity when solid, and exist as gases, liquids, or soft solids. Most organic compounds in Nigeria's petroleum industry contain countless covalent bonds between carbon and hydrogen atoms.

Covalent compounds form when atoms share electrons to create strong bonds. These substances have fascinating properties that make them different from ionic compounds. Most covalent compounds exist as gases, liquids, or soft solids at room temperature because the forces holding molecules together are weak. This is why sugar, which is covalent, melts easily when heated, unlike salt which requires much higher temperatures.

Covalent compounds generally have low melting and boiling points, meaning they don't need much energy to change state. They're also poor conductors of electricity since they don't have free-moving electrons or ions. Think of crude oil from Nigerian refineries—it's covalent and flows easily as a liquid. Additionally, many covalent compounds dissolve in non-polar solvents like petrol rather than water.

A coordinate bond, also called a dative bond, forms when one atom donates a pair of electrons to another atom that accepts them. Think of it like lending your friend money—you give, they receive, and you share the benefit. Both atoms end up sharing the electron pair, just like a normal covalent bond, but the difference is where those electrons came from initially.

The atom donating electrons must have a lone pair available, while the accepting atom must have an empty orbital. Once formed, coordinate bonds are just as strong as regular covalent bonds. A perfect Nigerian example is ammonia gas (NH₃) bonding with hydrogen ions to form ammonium ions (NH₄⁺). The nitrogen atom in ammonia donates its lone pair to the empty orbital of the hydrogen ion, creating a coordinate bond.

A covalent bond forms when two atoms share electrons with each other. Unlike ionic bonding where electrons transfer completely, covalent bonding is about sharing—think of it like two friends sharing a textbook instead of one owning it outright. The atoms share electrons in their outermost shells to achieve stability and complete their electron configurations.

Consider oxygen gas (O₂), which powers your breathing. Two oxygen atoms bond covalently by sharing two pairs of electrons, creating a strong double bond. This is why oxygen exists as O₂ rather than single O atoms in nature. Water (H₂O) is another everyday example where hydrogen and oxygen atoms share electrons covalently.

Covalent bonds typically occur between non-metal atoms. They're generally weaker than ionic bonds but can still be very strong, especially when multiple electron pairs are shared. This bonding explains why many substances have low melting points and don't conduct electricity when solid.