Chemistry Part 1 Notes

Chemistry Part 1 Notes

• Matter is anything that has mass and takes up space (solids, liquids, gases)
• Mass is the amount of matter in an object, measured in grams (g)
• Volume is the amount of space an object occupies, measured in cm³
• Physical properties describe the characteristics of a substance without changing its chemical composition (e.g., color, texture, melting point, boiling point, conductivity, solubility, malleability, viscosity)
• Chemical properties describe how a substance reacts with other substances (e.g., combustibility, reactivity with acids/bases/oxygen, lack of reactivity)
• States of matter include solids, liquids, and gases
  • Solids have a definite shape and volume
  • Liquids have a definite volume but take the shape of their container
  • Gases have neither a definite shape nor volume, taking the shape and volume of the container they're in
• The Particle Model of Matter describes matter as composed of tiny particles that are constantly vibrating and interacting with forces of attraction
• The Kinetic Molecular Theory (KMT) describes the behavior of matter at the particle level, stating that matter is composed of tiny particles, the particles are in constant motion, there are spaces between the particles, and energy makes particles move
• Chemical vs Physical changes
  • Physical changes do not change the chemical composition or identity of the substance, just the appearance.
    • Examples include melting ice, dissolving sugar, freezing water, and boiling water.
  • Chemical changes produce new substances or change chemical composition.
    • Examples include burning paper, reacting metals with acids, rusting of iron, cooking an egg, or baking a cake.

Describing Matter

• Matter can be described by its properties
  • Observable characteristics, like color or shape
  • Measurements, like density or conductivity
• Classifying matter includes:
  • Pure Substances:
    • Elements: substances composed of only one type of atom, like hydrogen (H) or oxygen (O)
    • Compounds: substances made up of two or more elements in a fixed ratio, arranged in a compound structure, such as water (H₂O) or salt (NaCl).
  • Mixtures: combinations of two or more pure substances that can be physically separated
    • Homogeneous mixtures have uniform composition throughout (e.g., saltwater solution)
    • Heterogeneous mixtures have uneven composition (e.g., a salad)

Investigating Matter

• Chemistry- is the study of matter, its properties, and how it changes.
• Chemical elements are substances that are made of one type of atom .
• An atom is the smallest unit of an element that retains the properties of that element
• Atoms are made up of positively charged protons, neutrally charged neutrons, and negatively charged electrons.
• The importance of studying chemical elements.

Atomic Theory

• Early ideas about matter proposed that matter was made of fundamental building blocks.
• Dalton's atomic theory describes atoms as small, indivisible particles.
  • All matter is made of atoms.
  • Atoms of a given element are identical.
  • Atoms of different elements are different.
  • Atoms combine in simple whole-number ratios to form compounds.
• Dalton's atomic theory was later refined to include subatomic particles, the structure of the atom, and isotopes

Atomic Structure

• Most of the atom's mass is concentrated in the nucleus which consists of protons and neutrons.
• Electrons orbit the nucleus.
• Properties of subatomic particles and the different types of subatomic particles
• Properties of subatomic particles (proton, electron, neutron - mass/charge/location)
  • Protons have a positive charge and are found in the nucleus.
  • Neutrons have no charge and are found in the nucleus.
  • Electrons have a negative charge and are found orbiting the nucleus.
• Atomic Structure Summary Table

Periodic Table

• The periodic table organizes elements based on their properties.
• Elements in the same group have similar chemical properties.
  • Elements are arranged in order of increasing atomic number
  • Groups (vertical columns) have similar properties
  • Periods (horizontal rows) show patterns in electron arrangement and properties.
  • Families of elements and their properties
  • Metals: typically lustrous, malleable, ductile, and good conductors of heat and electricity
    • Properties and characteristics of the various metal groups (alkali metals, alkaline earth metals, transition metals…)
  • Nonmetals: typically brittle, poor conductors of heat and electricity, and not lustrous
  • Metalloids: have properties that are intermediate between metals and nonmetals
• Electron configuration determines the arrangement of elements in the periodic table, and properties
• History of the periodic table
• The periodic table provides key information about elements and their properties

Chemical Bonds

• Ions are formed when atoms gain or lose electrons, leading to charges.
  • Atoms or ions with opposite charges attract each other.
  • The resulting attraction constitutes a chemical bond which are formed when atoms transfer electrons or share them.
• Multiple types of chemical bonds (ionic, covalent, metallic)
  • Formation and characteristics of ionic bonds
  • Formation and characteristics of covalent bonds

Bohr Diagrams

• Visual models representing the structure of atoms
• Identifying different subatomic particles (protons, neutrons, electrons)
• Electron arrangement in different energy levels (orbits)
• Valence electrons (electrons in the outermost shell) influence atomic behavior, such as bonding.
• Draw Bohr diagrams for different elements