Chemical Bonding and Periodic Table Trends

Definition: A chemical bond is a lasting attraction between atoms that enables the formation of chemical compounds.
Types of Bonds:
- Ionic Bonds: Formed between metals and nonmetals; involves transfer of electrons.
- Covalent Bonds: Formed between nonmetals; involves sharing of electrons.
- Metallic Bonds: Found in metals; involves a 'sea of electrons' shared among many atoms.
Bond Polarity:
- Nonpolar covalent: Equal sharing of electrons.
- Polar covalent: Unequal sharing of electrons.
- Ionic character: Degree of electron transfer in ionic bonds.

Atomic Radius:
- Decreases across a period (left to right) due to increased nuclear charge.
- Increases down a group due to additional electron shells.
Ionization Energy:
- Increases across a period as the attraction between nucleus and electrons increases.
- Decreases down a group as electrons are further from the nucleus.
Electronegativity:
- Increases across a period.
- Decreases down a group.
Electron Affinity:
- More negative across a period (greater tendency to gain electrons).
- Generally less negative down a group.

Types of Reactions:
- Synthesis: Two or more substances combine to form a compound (A + B → AB).
- Decomposition: A compound breaks down into simpler substances (AB → A + B).
- Single Replacement: An element replaces another in a compound (A + BC → AC + B).
- Double Replacement: Exchange of ions between two compounds (AB + CD → AD + CB).
- Combustion: Reaction with oxygen producing heat and light (Hydrocarbon + O₂ → CO₂ + H₂O).

Characteristics:
- Found in Groups 3 to 12 of the periodic table.
- Display properties such as variable oxidation states, formation of colored compounds, and catalytic activity.
Common Elements:
- Iron (Fe): Important in steel production and biological systems (hemoglobin).
- Copper (Cu): Good conductor of electricity, used in wiring and plumbing.
- Nickel (Ni): Resistant to corrosion, used in alloys and batteries.
Uses:
- Transition metals are integral in manufacturing, electronics, and as catalysts in chemical reactions.

A chemical bond represents a strong attraction between atoms that leads to the creation of chemical compounds.
Ionic Bonds occur between metals and nonmetals, characterized by the transfer of one or more electrons from one atom to another.
Covalent Bonds develop between nonmetals, allowing atoms to share electrons to achieve stability.
Metallic Bonds are present in metals, where electrons are delocalized, forming a 'sea of electrons' that contributes to conductivity and malleability.
Bond Polarity:
- Nonpolar covalent bonds involve equal electron sharing, resulting in balanced distribution.
- Polar covalent bonds occur when electrons are shared unequally, leading to partial charges.
- Ionic character quantifies the extent of electron transfer in ionic bonds.

Atomic Radius:
- Decreases across a period from left to right due to increasing nuclear charge attracting electrons more strongly.
- Increases down a group because additional electron shells are added, increasing distance from the nucleus.
Ionization Energy:
- Increases across a period, as stronger attraction between nucleus and electrons requires more energy to remove an electron.
- Decreases down a group, with outer electrons being further from the nucleus and easier to remove.
Electronegativity:
- Increases across a period, indicating a greater ability of an atom to attract and hold onto electrons.
- Decreases down a group as distance from the nucleus diminishes the attraction for electrons.
Electron Affinity:
- Generally becomes more negative across a period, indicating a stronger tendency to gain electrons.
- Becomes less negative down a group, showing a reduced inclination to gain electrons.

Synthesis Reaction: Involves the combination of two or more substances to form a single compound (A + B → AB).
Decomposition Reaction: A single compound breaks down into two or more simpler substances (AB → A + B).
Single Replacement Reaction: An element substitutes for another element in a compound (A + BC → AC + B).
Double Replacement Reaction: Involves an exchange of ions between two compounds (AB + CD → AD + CB).
Combustion Reaction: A chemical reaction with oxygen that produces heat and light, typically involving hydrocarbons (Hydrocarbon + O₂ → CO₂ + H₂O).

Transition elements are found in Groups 3 to 12 of the periodic table and possess unique properties such as variable oxidation states.
They often form colored compounds and are known for their catalytic abilities in chemical reactions.
Common Elements:
- Iron (Fe): Essential for steel production and critical in biological processes as a component of hemoglobin.
- Copper (Cu): Renowned for its electrical conductivity, widely used in wiring and plumbing applications.
- Nickel (Ni): Known for its corrosion resistance, frequently used in making alloys and batteries.
Transition metals play a significant role in various industries, including manufacturing and electronics, often acting as catalysts in chemical reactions.