Chemical Bonding and Properties Quiz

Chemical Bonding

• The process of atoms holding together in compounds.
• Three main types: ionic, covalent, and metallic.

Noble Gases

• Unreactive and monatomic due to stable outer electron shells.
• Used in providing inert atmospheres: Argon in lamps and Helium in balloons.

Halogens

• Range from gases (Fluorine, Chlorine) to liquids and solids down the group.
• Increasing atom size down the group due to more energy levels.
• Diverse uses in medicine, industry, and household products.

Alkali Metals

• Most reactive metals due to losing one electron for a stable outer shell.

### Physical Properties

• Luster: How shiny a substance is.
• Solubility: How easily a substance dissolves (e.g., table salt dissolving in water).
• Conductivity: How easily electrical current and heat pass through.
  • Good conductors (Copper wire) allow easy flow.
  • Poor conductors (insulators) resist flow (e.g., rubber).
• Ductility: How easily a substance bends.
  • Most metals are ductile at high temperatures.
  • Non-ductile materials (glass) are brittle and break easily when stretched.

Chemical Properties

• Describe the ability of a substance to change into new substances.

Reactivity

• Chemicals can react with other materials.
• Metals react with acids, producing new substances and gases (e.g., Magnesium reacting with acid, releasing hydrogen gas).

Flammability

• How easily a substance catches Fire (e.g., paper, gasoline).
• Burning involves chemical reactions, transforming substances into different ones.

Corrosion

• Iron and Steel corrosion is called "rusting."
• Rust is the red-brown substance formed.

Ions

• Charged particles with unequal numbers of protons and electrons.
• Formed by gaining or losing electrons.
• Cation: Positively charged ion (more protons than electrons).
• Anion: Negatively charged ion (more electrons than protons).

Diatomic Molecules

• Molecules composed of two atoms, either identical or different elements.

Elements

• Single atoms of elements are not molecules.
• Molecules are formed when elements bond to themselves or other elements (e.g., O2, O3, CO2).

Compounds

• Pure substances made of two or more different elements joined by chemical bonds.
• Chemical bonds can only be broken by other chemicals, not physically separated.

Example Tables

• Demonstrates the composition of molecules and compounds, including number of atoms, molecules, and elements.

Example 2: Dot and Cross Diagrams

• Illustrates how elements form bonds and the ions they create.

Periodic Table

• Non-metals are on the right side, metals on the left.
• Metals become more reactive down a period.
• Non-metals become less reactive down a period.

Groups

• Group 1: Alkali metals
• Group 2: Alkaline Earth metals
• Group 7: Halogens
• Group 8 (Group 0): Noble Gases

Let's Practice

1. Correct Answer: c. Covalent

• Halogens primarily form covalent bonds.

2. Correct Answer: a. They are Metals

• Halogens are non-metals.

3. Correct Answer: a. All form only -1 anions

• Halogens can form anions with different charges.