Subatomic Particles in Chemistry

Protons

• Positively charged subatomic particles
• Located in the nucleus of an atom
• Have a positive charge of +1 elementary charge
• Mass approximately 1 atomic mass unit (amu)
• Number of protons determines the element of an atom

Neutrons

• Subatomic particles with no charge
• Located in the nucleus of an atom
• Mass approximately 1 amu
• Number of neutrons determines the isotope of an element
• Plays a crucial role in nuclear reactions

Electrons

• Negatively charged subatomic particles
• Located outside the nucleus of an atom
• Have a negative charge of -1 elementary charge
• Very small mass compared to protons and neutrons
• Number of electrons equals the number of protons in a neutral atom
• Energy levels of electrons determine the chemical properties of an element

Atomic Structure

• Atoms consist of a nucleus (protons and neutrons) surrounded by electrons
• Electrons occupy specific energy levels or electron shells
• Innermost energy level (1s) can hold up to 2 electrons
• Subsequent energy levels can hold increasing numbers of electrons
• Electrons in the outermost energy level (valence shell) participate in chemical reactions

Nuclear Reactions

• Involve changes to the nucleus of an atom
• Examples:
  • Radioactive decay: spontaneous emission of radiation from an unstable nucleus
  • Nuclear fission: splitting of a heavy nucleus into lighter nuclei
  • Nuclear fusion: combination of light nuclei to form a heavier nucleus
• Nuclear reactions release or absorb a large amount of energy
• Have applications in energy production, medicine, and scientific research

Subatomic Particles

• Protons: positively charged, located in the nucleus, +1 elementary charge, 1 amu mass, determines the element
• Neutrons: no charge, located in the nucleus, 1 amu mass, determines the isotope of an element, crucial in nuclear reactions
• Electrons: negatively charged, located outside the nucleus, -1 elementary charge, very small mass, number equals protons in a neutral atom, energy levels determine chemical properties

Atomic Structure

• Atoms consist of a nucleus (protons and neutrons) and electrons
• Electrons occupy specific energy levels or electron shells
• Electron shells:
  • Innermost (1s): holds up to 2 electrons
  • Subsequent shells: hold increasing numbers of electrons
  • Outermost (valence shell): electrons participate in chemical reactions

Nuclear Reactions

• Involve changes to the nucleus of an atom
• Types:
  • Radioactive decay: spontaneous emission of radiation from an unstable nucleus
  • Nuclear fission: splitting of a heavy nucleus into lighter nuclei
  • Nuclear fusion: combination of light nuclei to form a heavier nucleus
• Characteristics:
  • Release or absorb a large amount of energy
  • Applications in energy production, medicine, and scientific research