Ions, Ionic Bonds and Compounds

• An ion is an atom or molecule that has gained or lost one or more electrons, giving it an electrical charge.
• A cation is a positively charged ion formed when an atom loses electrons.
• An anion is a negatively charged ion formed when an atom gains electrons.
• Ionic charge refers to the positive or negative charge on an ion, resulting from the loss or gain of electrons.
• Combining capacity is the ability of an element to form chemical bonds with other elements, often indicated by its valency.
• Valence electrons are the electrons in the outermost shell of an atom that participate in bonding.
• A stable octet refers to the tendency of atoms to achieve eight valence electrons to mimic the stability of noble gases.
• A polyatomic ion is an ion composed of multiple atoms bound together, carrying an overall charge.
• A binary compound contains two different elements.
• A ternary compound contains three different elements.
• An ionic bond is formed through electrostatic attraction between oppositely charged ions, typically between a metal and a nonmetal.
• A covalent bond involves the sharing of electron pairs between atoms, usually between two nonmetals.
• A molecule is a neutral group of two or more atoms held together by covalent bonds.
• A binary covalent compound is formed by covalent bonding between two nonmetals.
• A reactant is a substance that undergoes change during a chemical reaction.
• A product is a substance that is produced as a result of a chemical reaction.
• A chemical reaction is a process converting reactants into products.
• A chemical equation symbolically represents a chemical reaction, indicating the reactants, products, and their states.
• A coefficient is a number placed before a chemical formula in an equation to balance it.
• An acid donates protons (H+) in solution and typically has a pH less than 7.
• A base accepts protons (H+) or donates hydroxide ions (OH-) in solution, typically having a pH greater than 7.
• Ionization is the process of forming ions by gaining or losing electrons or the dissociation of acids and bases into ions.
• Dissociation is the process by which an ionic compound separates into its ions in a solution.
• The pH scale measures the acidity or basicity of a solution, ranging from 0 to 14.
• Neutralization is a reaction between an acid and a base to form water and a salt, reducing acidity or basicity.
• Matter has mass and takes up space, excluding forms of energy such as sound, light, and heat.
• Matter is classified by chemical and physical properties.

Properties and Changes

• Physical properties can be observed directly, for example, color, smell, and taste.
• Chemical properties describe how a substance reacts chemically, such as flammability, pH, and solubility.
• Physical changes alter the appearance or state of matter without changing its chemical composition, like water freezing.
• Chemical changes result in the formation of a new substance with different chemical properties and are often irreversible, such as baking a cake.

Pure Substances vs Mixtures

• Pure substances include elements and compounds.
• Mixtures are classified as homogeneous or heterogeneous.
• Homogeneous mixtures have uniform composition where ingredients are not visible, for example, orange juice.
• Heterogeneous mixtures have non-uniform composition where ingredients are visible, for example, pizza.

The Periodic Table

• Metals are on the left side of the periodic table, while nonmetals are on the right.
• Periods are horizontal rows which indicates the number of electron shells an atom has.
• Groups are vertical columns that indicates the number of electrons in the outermost shell.
• The atomic number indicates the number of electrons orbiting the nucleus.
• The atomic mass is the total number of protons and neutrons in an atomic nucleus.
• Valence electrons are located on the outermost shell of an atom.

Families in Periodic Table

• Alkali metals are in Group 1A.
• Alkaline earth metals are in Group 2A.
• Transition metals are located in the middle of the periodic table.
• Halogens are in Group 7A.
• Noble gases are in Group 8A.
• Metalloids are along the staircase line.

Drawing Bohr-Rutherford Diagrams

• Represent the nucleus as a solid circle.
• Include the number of protons (atomic number) and neutrons in the nucleus.
• Find the number of neutrons by subtracting the atomic number from the atomic mass.
• Place the number of electrons in orbits around the nucleus, following the rule of 2 electrons in the 1st shell, 8 in the 2nd, and 8 in the 3rd.

Atoms vs Ions

• Atoms are electrically neutral.
• The number of protons equals the number of electrons in an atom.
• Protons are positively charged and located in the nucleus.
• Electrons are negatively charged and orbit the nucleus.
• Neutrons have no charge and are located in the nucleus.
• Atomic number equals number of protons and electrons.
• Neutrons equals mass number minus atomic number.
• Ions are atoms that have gained or lost electrons, resulting in a charge.
• Cations are ions with a positive charge due to lost electrons.
• Anions are ions with a negative charge due to gained electrons.

Types of Compounds

• Binary ionic compounds are formed when a metal reacts with a nonmetal.

Explaining Roman Numerals

• Roman numerals indicate the charge of a transition metal in an ionic compound, since transition metals can have multiple charges.
• Roman numerals follow the criss-cross rule.
• Example: Copper (II) Chloride = CuCl₂

Ionic Compounds (Criss-Cross)

• Potassium chloride: KCI
• Lithium Oxide: Li2O
• Calcium Bromide: CaBr2
• Always add "ide" to the end of the name.

Writing Ionic Formulas (Criss-cross)

• Silver oxide - Ag2O
• Aluminum nitride - Al3N3
• Magnesium nitride - Mg3N2
• Calcium hydride- CaH2

Binary Covalent Compounds (Molecular)

• These compounds are formed when two nonmetals react.
• Covalent prefixes indicate the number of each element in the compound.
• Dihydrogen Oxide: H2O
• Carbon dioxide: CO2
• Boron trichloride: BCl3

Covalent prefixes

• Mono
• Di
• Tri
• Tetra
• Penta

Polyatomic Ions

• Groups of two or more atoms that stick together and have an overall charge.
• They act like a single unit in chemical reactions.
• Example - Sulfate (SO₄²⁻) has one sulfur atom and four oxygen atoms,.and it has a -2 charge.
• Only Criss-Cross the charge outside of the bracket.
• Example - Ba(NO₃)² = Ba₂NO₃

Word, Skeleton and Balanced Chemical Equations

• Word equations describe chemical reactions using the names of substances.
• Reactant 1 + Reactant 2 → Product 1 + Product 2
• Include Roman numerals for transition metals without criss-crossing.
• Example: Aluminum + Oxygen -> Aluminum Oxide
• Skeleton equations represent reactions using chemical formulas without balancing.
• Criss-cross method must be applied to write formulas correctly.
• Example: Al₃ + O₂ -> Al₂O₃
• Balancing equations ensures the number of atoms are equal on both sides.
• The Law of Conservation states mass of reactants equals mass of products.
• Example: 2Fe + 3H₂SO₄ -> Fe₂(SO₄)₃ + 3H₂

Diatomic molecules

• IHNFCLBRO (H₂, N₂, O₂, Cl₂, Br₂, I₂, and F₂)

Classifying Chemical Reactions

• Synthesis is when 2 simple elements (reactants) combine to form 1 larger and more complex molecule (product)
• Decomposition is the reverse of synthesis.
• Single displacement reactions occur when one element displaces another in a compound.
• Double displacement reactions occur when two elements in different compounds trade places.
• Combustion reactions involve a fuel reacting rapidly with oxygen, releasing energy as heat and light.

Acids

• An aqueous solution that:
• Conducts electricity
• Tastes sour
• Turns blue litmus red
• Neutralizes bases

Bases

• An aqueous solution that:
• Feels slippery
• Taste bitter
• Conducts electricity
• Turns red litmus blue

pH Scale

• Measures the concentration of hydrogen ions (H+) in a solution.
• Each increment represents a factor of 10.
• Solutions with a high concentration of hydrogen ions = Acidic.
• Solutions with a low concentration of hydrogen ions = Basic or Alkaline.
• The scale ranges from 0-14
• pH 0 :being most acidic - High concentration of H+.
• pH 14 = most basic - Low concentration of H+ /High concentration of OH-.
• pH 7 = neutral - Equal concentrations of H+ and OH- .

Naming Acids

• Binary acids contains two elements.
• Oxyacids contains polyatomic ions.
• Add Hydro to the beginning (H if it is a formula)
• Always use the criss cross method with charges
• Ite = ous
• Ate = ic
• If a roman numeral is next to a transition element, Still use Criss Cross Method

Rules for Oxyacids

• Drop the “Hydro”, Keep the H in the formula
• Add Acid at the end of every Acid
• Ite = ous
• Ate = ic