Science Chapter: Matter and Classification

Matter and Classification of Matter

• Matter is anything that has mass and occupies space
• Matter is classified as elements, compounds, and mixtures
• Pure substances are either elements or compounds, and are uniform in composition
• Mixtures combine two or more substances, but do not have a uniform composition

Motion of Particles (Kinetic Energy) in Different States of Matter

• Particles of matter are constantly in motion
• The kinetic energy of particles affects the state of matter
  • Solids have low kinetic energy and fixed positions
  • Liquids have medium kinetic energy and can move past each other
  • Gases have high kinetic energy and can move freely

Introduction to Atoms and Molecules

• Matter is made up of tiny particles called atoms
• Molecules are formed when two or more atoms bond together

Elements and Compounds

• Elements are pure substances made of only one type of atom
• Compounds are pure substances made of two or more different types of atoms bonded together

Physical and Chemical Properties

• Physical properties can be observed without changing the composition of a substance
• Examples of physical properties include color, density, and melting point
• Chemical properties describe how a substance reacts with other substances to form new substances

Physical and Chemical Change-Phase Change is a Physical Change

• Physical changes alter a substance's physical properties but do not change its composition
• Phase changes are examples of physical changes
• Chemical changes result in the formation of new substances with different properties

Atomic Structure

• Atoms have a central nucleus containing protons and neutrons, with electrons orbiting the nucleus

Subatomic Particles: Proton, Electron, and Neutron

• Protons: positively charged particles located in the nucleus
• Electrons: negatively charged particles orbiting the nucleus
• Neutrons: neutral particles located in the nucleus

Atomic Number, Atomic Symbol, Mass Number, Different Representation of Element

• Atomic number: the number of protons in an atom
• Atomic symbol: a one- or two-letter abbreviation for an element
• Mass number: the sum of protons and neutrons in an atom

Valence Electrons and Electron Dot Symbol

• Valence electrons are the electrons in the outermost energy level of an atom
• Electron dot symbols represent the valence electrons of an element as dots around the element's symbol

Determination of Electrons in Neutral Atoms and Charged Ions

• Neutral atoms have an equal number of protons and electrons
• Ions have a different number of protons and electrons, resulting in a positive or negative charge

Calculation of Average Atomic Mass

• Average atomic mass is calculated by considering the abundance of isotopes of an element

Different Types of Bonds Depending on Electronegativity Difference: Ionic and Covalent

• Ionic bonds form between metals and nonmetals
• Covalent bonds form between nonmetals
• Electronegativity difference dictates the type of bond

Distinguish between Properties of Ionic and Covalent Compounds

• Ionic compounds are typically crystalline solids with high melting and boiling points, and conductive when melted or dissolved
• Covalent compounds are typically gases, liquids, or low-melting solids with low melting and boiling points; and not conductive (generally)

Naming of Ionic and Covalent Compounds

• Ionic compound naming follows specific rules based on the ions present
• Covalent compound naming uses prefixes to indicate the number of atoms of each element

Polyatomic Ions

• Polyatomic ions are groups of atoms that carry a charge and act as a single unit

Naming of Ionic Compounds with Transition Elements and Polyatomic Ions

• Naming ionic compounds with transition metals requires use of Roman numerals to indicate the charge of the transition metal ion

Drawing Electron Dot Structures of Ionic and Covalent Compounds

• Electron dot structures show how valence electrons are arranged in atoms and molecules

Determine the Molecular Structure Using VSEPR (Valence Shell Electron Pair Repulsion) Theory

• VSEPR theory predicts the shapes of molecules based on the repulsion between electron pairs

Metallic Bonding and Properties Related to Metal Bonding: Ductility, Thermal and Electrical Conductivity, Malleability

• Metallic bonding involves a "sea" of delocalized electrons that hold metal atoms together
• Properties like ductility, thermal and electrical conductivity, and malleability result from the mobile electrons in the metallic bond