Atoms and Molecules
Explore the fundamental building blocks of matter - atoms, their structure, and how they combine to form molecules through chemical bonding.
Key Topics & Instructions
▼- Atomic Structure: Understand protons, neutrons, electrons and atomic models.
- Chemical Bonding: Learn about ionic, covalent and metallic bonds.
- Molecular Formation: Explore how atoms combine to form molecules.
- Atomic Mass & Moles: Study atomic mass units and the mole concept.
- Atomic Structure: Select different elements to see their atomic structure.
- Molecular Formation: Choose bonding types to understand molecular creation.
- Electron Arrangement: Observe electron configuration in different atoms.
- Review the explanations for understanding atomic and molecular concepts.
Experiment 1: Atomic Structure
Select different elements to explore their atomic structure, electron configuration, and properties.
Experiment 2: Molecular Formation
Select different bonding types to understand how atoms combine to form molecules and compounds.
An atom is the basic unit of matter consisting of a central nucleus containing protons (positively charged) and neutrons (neutral), surrounded by electrons (negatively charged) in specific energy levels or shells. The atomic number equals the number of protons, while the mass number is the sum of protons and neutrons. Electrons occupy different shells (K, L, M, N) with specific capacity limits (2, 8, 18, 32).
Chemical Bonding and Molecular Formation
Ionic bonding occurs when atoms transfer electrons to achieve stable electron configurations. Metals lose electrons to form positively charged cations, while non-metals gain electrons to form negatively charged anions. The electrostatic attraction between oppositely charged ions creates ionic bonds. Examples include sodium chloride (NaCl) where sodium donates an electron to chlorine.
Covalent bonding involves the sharing of electron pairs between atoms. This type of bonding typically occurs between non-metal atoms. Single, double, or triple bonds form depending on how many electron pairs are shared. Examples include water (H₂O) where oxygen shares electrons with two hydrogen atoms, and oxygen gas (O₂) with a double covalent bond.
Metallic bonding occurs in metal elements where positively charged metal ions are surrounded by a "sea" of delocalized electrons. These free-moving electrons are responsible for metals' high electrical and thermal conductivity, malleability, and ductility. The strength of metallic bonds increases with the number of delocalized electrons.
Hydrogen bonding is a special type of dipole-dipole attraction that occurs when hydrogen is bonded to highly electronegative atoms like oxygen, nitrogen, or fluorine. Though weaker than covalent or ionic bonds, hydrogen bonds significantly affect physical properties like boiling points and solubility. They are crucial in biological systems like DNA structure and protein folding.
The atomic mass unit (amu) is defined as 1/12th the mass of a carbon-12 atom. The mole is the SI unit for amount of substance, defined as exactly 6.022 × 10²³ elementary entities (Avogadro's number). This concept allows chemists to count atoms and molecules by weighing macroscopic amounts of substances.
Molecular formulas show the actual number of atoms of each element in a molecule. Structural formulas display how atoms are connected. Isomers are compounds with the same molecular formula but different structural arrangements. Understanding molecular structure helps predict chemical behavior and properties of substances.
