General Chemistry Concepts and Atomic Structure

General Chemistry Concepts

• Chemistry is the study of matter and its properties, the changes it undergoes, and the energy associated with those changes.
• Matter is anything that has mass and occupies space.
• Atoms are the fundamental building blocks of matter. They consist of a nucleus (containing protons and neutrons) and electrons orbiting the nucleus.
• Elements are pure substances composed of only one type of atom.
• Compounds are substances formed by the chemical combination of two or more different elements in a fixed ratio.
• Molecules are groups of two or more atoms held together by chemical bonds.
• Chemical reactions are processes in which substances (reactants) are transformed into new substances (products).

Atomic Structure and Periodic Table

• The periodic table is an arrangement of elements based on their atomic number (number of protons) and recurring chemical properties.
• Atomic number (Z) is the number of protons in an atom's nucleus.
• Mass number (A) is the sum of protons and neutrons in an atom's nucleus.
• Isotopes are atoms of the same element with different numbers of neutrons.
• Atomic mass is the weighted average of the masses of all isotopes of an element.
• Groups on the periodic table are vertical columns and contain elements with similar chemical properties.
• Periods on the periodic table are horizontal rows and show trends in properties as the atomic number increases.

Chemical Bonding

• Ionic bonding involves the electrostatic attraction between oppositely charged ions.
• Covalent bonding involves the sharing of electrons between atoms.
• Metallic bonding involves the attraction between positively charged metal ions and a "sea" of delocalized electrons.

States of Matter

• Solids have a fixed shape and volume.
• Liquids have a fixed volume but take the shape of their container.
• Gases have neither a fixed shape nor a fixed volume.

Stoichiometry

• Stoichiometry is the calculation of reactants and products in chemical reactions.
• Moles are a unit of amount of substance.
• Molar mass is the mass of one mole of a substance.
• Mole ratios are used to determine the quantities of reactants and products in a balanced chemical equation.

Chemical Reactions

• Precipitation reactions result in the formation of an insoluble solid.
• Acid-base reactions involve the transfer of protons.
• Redox reactions involve the transfer of electrons.
• Titration is a technique used to determine the concentration of a solution.