Elements and Compounds: Particle Theory of Matter

Elements and Compounds

• An element is a substance that consists of only one type of atom.
• A compound is a substance that consists of two or more different elements, chemically bonded together.

Particle Theory of Matter

• All matter is made up of tiny particles called atoms and molecules.
• All particles of a pure substance are the same and are different from particles of another pure substance.
• Particles are always moving, and their motion increases with temperature.
• Particles attract each other, with stronger forces when closer together.

Physical Properties

• Physical state: solid, liquid, or gas.
• Hardness: resistance to being scratched or dented.
• Malleability: ability to be bent into different shapes.
• Ductility: ability to be pulled into long thin wires.
• Melting and boiling points: temperatures at which a substance changes state.
• Solubility: ability of a substance to dissolve.
• Viscosity: measure of how easily a liquid flows.
• Density: amount of matter per unit volume of that matter.

Chemical Properties

• Combustibility: ability of a substance to burn.
• Reactivity: how easily a substance reacts with another substance.
• Sensitivity to light: how a substance reacts when exposed to light.

Density Calculations

• Density formula: D = mass / volume.
• Example: Density of a substance with a mass of 39.5 g and a volume of 22L is 1.8 g/L.
• Example: Density of a basketball with a mass of 758 g and a volume of 344.55 mL is 2.20 g/mL.

Atomic Notation

• Technetium: 99Tc43.

Atomic Structure

• Number of protons, neutrons, and electrons in Astatine: 85, 125, and 85 respectively.

Isotopes

• Isotopes are two or more forms of an element with the same number of protons and different numbers of neutrons.

Man-made Elements

• Elements 93-103 are man-made.

Element Classification

• Hydrogen is not an Alkali Metal.

Insulators and Conductors

• An insulator is a material that prevents the flow of electricity, while a conductor is a material that allows the flow of electricity.

Electrostatic Series

• The electrostatic series is the order of materials that can be charged by rubbing against each other.
• Examples of electrostatic series include:
  • Rubbing paper with wax: Paper becomes negative, wax becomes positive.
  • Rubbing a Taqwa hoodie with glass: Hoodie becomes negative, glass becomes positive.
  • Rubbing a plastic comb with a sheep: Comb becomes negative, sheep wool becomes positive.

Transferring Electrical Charges

• There are three ways to transfer electrical charges:
  • Friction: Objects made of different materials are rubbed together, producing a static net charge on each object.
  • Contact: Charging by contact occurs when a charged object touches a neutral object, causing electrons to move to balance the charges.
  • Induction: A charged object can transfer a charge to a neutral object without touching it, only possible with conductors.

Discharging Electrical Objects

• There are two methods to discharge an electrical object:
  • Grounding: Connecting the object to the ground to remove excess charge.
  • Discharge at a point: Discharging the object at a specific point to remove excess charge.

Circuit Diagrams

• A 3-cell, complete, controlled circuit with a variable resistor can be drawn as follows:
  • [Insert diagram]
• A fused, parallel circuit with a 4-cell battery and 4 light bulbs (minimum 2 in series) can be drawn as follows:
  • [Insert diagram]

Measuring Current

• The equation to measure current is: [Insert equation]