Understanding Elements and Atoms

Observations of Substances

• Humans have observed different substances for thousands of years.
• Substances have distinct properties: color, state (solid, liquid, gas), interaction with light.
• Substances may react differently under certain conditions.

Elements

• Elements are pure substances with specific properties.
• Common examples include Carbon, Lead, and Gold.
• Elements are listed on the Periodic Table.
  • C for Carbon
  • O for Oxygen
  • N for Nitrogen
  • Si for Silicon
  • Au for Gold
  • Pb for Lead

The Atom

• The smallest unit of an element that retains the properties of that element.
• Examples:
  • Carbon atom
  • Gold atom
  • Lead atom
• Atoms are incredibly small; for instance, a human hair is approximately a million carbon atoms wide.

Fundamental Particles of Atoms

• Atoms are composed of protons, neutrons, and electrons.

Protons

• Define the element.
• The number of protons equals the atomic number.
  • Hydrogen: 1 proton
  • Helium: 2 protons
  • Carbon: 6 protons
  • Oxygen: 8 protons
• Changing the number of protons results in a different element.

Neutrons

• Found in the nucleus with protons.
• Can vary in number without changing the element.
• Example: Carbon-12 vs. Carbon-14 (difference in neutrons).

Electrons

• Move around the nucleus.
• Responsible for chemical reactions and bonding.
• Electrons have a negative charge, balancing the positive charge of protons.

Atomic Structure

• Nucleus: Contains protons and neutrons.
  • Example: Carbon-12 nucleus has 6 protons and 6 neutrons.
• Electrons: Orbit or buzz around the nucleus.
  • Number of electrons can change, affecting charge without altering the element.

Charge and Reactions

• Protons (positive charge) attract electrons (negative charge).
• Neutrons have no charge, impacting some properties of elements.
• Chemistry is largely defined by electron interactions and configurations.
• Atoms can gain or lose electrons, affecting their charge and reactions.

Conclusion

• Atoms are the basic building blocks of elements.
• Understanding atomic structure is fundamental to understanding chemistry and how elements interact.