1: Introduction to Chemistry, the Periodic Table, and Ionic Compounds
- Page ID
- 283304
\( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}} } \) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash {#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\)
- 1.1: Using the Scientific Method
- Scientists search for answers to questions and solutions to problems by using a procedure called the scientific method. This procedure consists of making observations, formulating hypotheses, and designing experiments, which in turn lead to additional observations, hypotheses, and experiments in repeated cycles
- 1.2: Defining Chemistry
- Chemistry is the study of matter and the changes it undergoes.
- 1.3: Classification of Matter
- Classifying or grouping substances makes it easier to study their properties. Two ways to classify substances are by state of matter (solid, liquid, or gas) and by chemical composition (element, compound, or mixture).
- 1.4: Physical and Chemical Changes
- A physical change is a change to a sample of matter in which some properties of the material change, but the identity of the matter does not. In contrast, a chemical property describes the ability of a substance to undergo a specific chemical change.
- 1.5: Atomic Theory
- Chemistry is based on the modern atomic theory, which states that all matter is composed of atoms. Atoms themselves are composed of protons, neutrons, and electrons. Each element has its own atomic number, which is equal to the number of protons in its nucleus. Isotopes of an element contain different numbers of neutrons. Elements are represented by an atomic symbol. The periodic table is a chart that organizes all the elements.
- 1.6: The Periodic Table
- The discovery of the periodic recurrence of similar properties among the elements led to the formulation of the periodic table, in which the elements are arranged in order of increasing atomic number in rows known as periods and columns known as groups. Elements in the same group of the periodic table have similar chemical properties. Elements can be classified as metals, metalloids, and nonmetals, or as a main-group elements, transition metals, and inner transition metals.
- 1.7: The Importance of Ions
- Chemists appreciate isotopes and use them in basic and applied research. However, they are more concerned with the movement of electrons. When an atom gains or loses electrons, it becomes a charged species or an ion. When this occurs, the nucleus is not altered. For atoms that lose electrons, an overall positive charge will result (#protons > #electrons). Atoms that form these types of ions are called cations.
- 1.8: Ionic and Covalent Bonds
- There are many types of chemical bonds and forces that bind molecules together. The two most basic types of bonds are characterized as either ionic or covalent. In ionic bonding, atoms transfer electrons to each other. Ionic bonds require at least one electron donor and one electron acceptor. In contrast, atoms with the same electronegativity share electrons in covalent bonds, because neither atom preferentially attracts or repels the shared electrons.
- 1.9: Formulas for Ionic Compounds
- Proper chemical formulas for ionic compounds balance the total positive charge with the total negative charge. Groups of atoms with an overall charge, called polyatomic ions, also exist.