Difference between compounds,molecules and mixtures

• What are the three important terms to understand about atoms?

  Molecules, mixtures, and compounds
• How is a molecule defined?

  A group of two or more atoms bonded together
• Can molecules contain multiple different elements?

  Yes, for example, water molecules
• What is the composition of a water molecule?

  One oxygen and two hydrogen atoms
• Why is helium not considered a molecule?

  It exists as a single atom
• What defines a compound?

  Substances with two or more different elements
• Which of the following is a compound?

  Water
• What is a key feature of compounds regarding element proportions?

  Elements are always in the same proportions
• What does the subscript in a chemical formula signify?

  The number of atoms of that element
• What is the formula for carbon dioxide?

  CO₂
• How do brackets function in chemical formulas?

  They group atoms and indicate quantity
• How do ionic bonds affect the structure of compounds?

  They form large structures, not molecules
• What is the formula for sodium chloride?

  NaCl
• What does the formula NaCl represent in terms of ratio?

  One sodium ion to one chloride ion
• What is a mixture?

  Two or more substances not chemically combined
• How can you separate components of a mixture?

  Using physical methods like filtration
• What are the differences between molecules, compounds, and mixtures?

  • Molecules: Groups of two or more atoms bonded.
  • Compounds: Substances with two or more different elements.
  • Mixtures: Two or more substances not chemically combined.
• What are the characteristics of compounds and how do they differ from molecules?

  • Compounds contain different elements in fixed proportions.
  • Molecules can consist of one or multiple elements.
  • Compounds are formed through chemical bonds, while mixtures are not.