Elements and Mixtures

Elements

• A substance that consists of only one type of atom
• Cannot be broken down into simpler substances by chemical means
• 118 known elements, each with a unique atomic number (number of protons in the nucleus)
• Examples: hydrogen (H), carbon (C), oxygen (O)

Mixtures

• A physical blend of two or more substances, where each substance maintains its chemical properties
• Can be separated into individual components by physical means (e.g., filtration, sedimentation)
• Properties of a mixture vary depending on the proportion of each component
• Examples: air (oxygen, nitrogen, carbon dioxide), soil (sand, silt, clay)

Compounds

• A substance formed by the chemical combination of two or more different elements
• Have unique properties different from the individual elements
• Can be broken down into simpler substances by chemical means
• Examples: water (H2O), carbon dioxide (CO2), sodium chloride (NaCl)

Pure Substances

• A substance that has a fixed composition and properties
• Can be either an element or a compound
• Has a unique set of physical and chemical properties
• Examples: pure water, pure sodium chloride (table salt)

Separation Techniques

Physical Separation Techniques

• Filtration: separating a mixture based on differences in particle size
• Sedimentation: separating a mixture based on differences in density
• Decantation: separating a mixture based on differences in density
• Crystallization: separating a mixture based on differences in solubility

Chemical Separation Techniques

• Distillation: separating a mixture based on differences in boiling points
• Chromatography: separating a mixture based on differences in affinity for a stationary phase
• Electrolysis: separating a mixture based on differences in electrical conductivity

Elements

• Consist of only one type of atom
• Cannot be broken down into simpler substances by chemical means
• 118 known elements, each with a unique atomic number (number of protons in the nucleus)
• Examples: hydrogen (H), carbon (C), oxygen (O)

Mixtures

• A physical blend of two or more substances, where each substance maintains its chemical properties
• Can be separated into individual components by physical means (e.g., filtration, sedimentation)
• Properties of a mixture vary depending on the proportion of each component
• Examples: air (oxygen, nitrogen, carbon dioxide), soil (sand, silt, clay)

Compounds

• Formed by the chemical combination of two or more different elements
• Have unique properties different from the individual elements
• Can be broken down into simpler substances by chemical means
• Examples: water (H2O), carbon dioxide (CO2), sodium chloride (NaCl)

Pure Substances

• Have a fixed composition and properties
• Can be either an element or a compound
• Have a unique set of physical and chemical properties
• Examples: pure water, pure sodium chloride (table salt)

Separation Techniques

Physical Separation Techniques

• Filtration: separates a mixture based on differences in particle size
• Sedimentation: separates a mixture based on differences in density
• Decantation: separates a mixture based on differences in density
• Crystallization: separates a mixture based on differences in solubility

Chemical Separation Techniques

• Distillation: separates a mixture based on differences in boiling points
• Chromatography: separates a mixture based on differences in affinity for a stationary phase
• Electrolysis: separates a mixture based on differences in electrical conductivity

Learn about the basics of elements and mixtures, including their definitions, properties, and differences. This quiz covers the fundamentals of chemistry and the physical sciences.