Lecture on Basic Atomic Structure

Introduction

• Focus on AIT's Version 7 Science, specifically Chemistry.
• Begin with the basic atomic structure.

Atomic Structure

• Atoms are fundamental building blocks of matter.
• Central nucleus contains protons (positive charge) and neutrons (no charge).
• Electrons (negative charge) orbit the nucleus in constant motion.

Electrical Charge

• Protons have a charge of +1.
• Electrons have a charge of -1.
• Neutrons have no charge.
• Opposite charges attract, maintaining atomic structure integrity.

Mass of Atoms

• Most mass concentrated in nucleus (protons and neutrons).
• Protons and neutrons each weigh ~1 atomic mass unit (amu).
• Electrons weigh ~0.000549 amu, negligible in atomic mass calculations.

Periodic Table

• Each element has an atomic number (protons) and atomic mass (protons + neutrons).
• "Pan Man" mnemonic: P (Protons), A (Atomic number), N (Number of protons); M (Mass number), A (Add), N (Neutrons).

Isotopes

• Atoms of the same element with different numbers of neutrons.
• Example: Carbon isotopes (Carbon-12, Carbon-13, Carbon-14).
  • Carbon-12 has 6 protons and 6 neutrons.
  • Carbon-13 has 6 protons and 7 neutrons.
  • Carbon-14 has 6 protons and 8 neutrons.

Ions

• Atoms or groups of atoms with a net electrical charge.
• Formed by gaining or losing electrons.
• Example: Sodium loses an electron → Na+ (cation); Oxygen gains electrons → O2- (anion).
• Mnemonics: Cation = "cat ion" for positive; Anion = "a negative onion" for negative.

Shells, Subshells, and Orbitals

• Electrons orbit in shells (energy levels) denoted by n.
• Shells contain subshells (s, p, d, f).
• Orbitals: 3D space where an electron is likely found.
• Each subshell can hold a specific number of electrons:
  • n=1 (1s): max 2 electrons
  • n=2 (2s, 2p): max 8 electrons
  • n=3 (3s, 3p, 3d): max 18 electrons
  • n=4 (4s, 4p, 4d, 4f): max 32 electrons

Chemical Bonds

• Ionic Bonds: Transfer of electrons between atoms (sodium chloride example).
• Covalent Bonds: Sharing of electron pairs between atoms (carbon dioxide example).
• Mnemonics: Ionic - "I take, you give"; Covalent - "Sharing is caring".

Periodic Table Organization

• Periods (rows): Indicate number of electron shells.
• Groups (columns): Elements with similar properties.

Practice Questions

1. Ionic Bond Formation: Electrons are transferred (B).
2. Covalent Bond Description: Atoms share electrons (A).
3. Octet Rule Influence: Electron configuration (C).
4. Elements in Same Period: Same number of electron shells (B).

Conclusion

• Understanding basic atomic structure is crucial for exams.
• Additional resources available at nursechunkstore.com.