Intro to Chemistry: Elements and Compounds

Introduction to Chemistry

• The periodic table is a fundamental tool in chemistry, and it's recommended to print one out and familiarize yourself with it.
• The elements in Group 1 (alkali metals) tend to form ions with a positive one charge, while those in Group 2 (alkaline earth metals) form ions with a positive two charge.

Atoms and Molecules

• Elements can be composed of atoms or molecules.
• A pure element consists of one type of atom, while a compound consists of different types of atoms.
• Hydrogen, oxygen, nitrogen, and fluorine are examples of molecules, while zinc, iron, and aluminum are pure elements.

Metals, Non-metals, and Metalloids

• Elements can be classified as metals, non-metals, or metalloids based on their properties.
• Metals tend to conduct electricity, non-metals are insulators, and metalloids have intermediate properties.
• The periodic table can be used to identify metals, non-metals, and metalloids.

Compounds

• Compounds can be classified as ionic or molecular.
• Ionic compounds consist of ions, while molecular compounds consist of molecules.
• Ionic compounds are typically formed between metals and non-metals, while molecular compounds are formed between non-metals.

Naming Compounds

• Molecular compounds are named based on the number of atoms of each element in the molecule.
• Ionic compounds are named based on the metal and non-metal ions, with Roman numerals used to indicate the charge on the metal ion.
• Polyatomic ions are ions that consist of multiple atoms, such as sulfate (SO42-) and hydroxide (OH-).

Examples of Compounds

• Sulfur trioxide (SO3) is a molecular compound.
• Carbon dioxide (CO2) is a molecular compound.
• Lithium bromide (LiBr) is an ionic compound.
• Potassium iodide (KI) is an ionic compound.
• Calcium oxide (CaO) is an ionic compound.
• Sodium sulfate (Na2SO4) is an ionic compound.

Important Concepts

• Valence electrons: the electrons in the outermost energy level of an atom.
• Oxidation states: the charge on an atom in a compound.
• Roman numerals: used to indicate the charge on a metal ion in an ionic compound.

Examples to Try

• Naming molecular compounds: CO, N2O5
• Naming ionic compounds: MgBr2, CaO
• Identifying polyatomic ions: NO3-, PO43-
• Writing formulas for ionic compounds: iron(II) chloride, iron(III) chloride### Solving for Oxidation States
• To solve for Pb, set the equation equal to zero, considering the charge of oxygen (-2) and the total negative charge, which leads to the oxidation state of Pb being +4.
• The compound is named lead(IV) oxide.

Naming Ionic Compounds

• Cu2SO4 is named copper(I) sulfate.
• The oxidation state of copper is +1, confirmed by two methods:
  • Equation method: 2Cu = +2, Cu = +1.
  • Ion method: total positive charge = total negative charge, so 2Cu = +2, Cu = +1.

Writing Formulas of Compounds

• Molecular compounds: reverse the naming process.
  • Phosphorus pentachloride: PCl5.
  • Sulfur tetrafluoride: SF4.
  • Nitrogen monoxide: NO.
• Ionic compounds: balance the charges of the ions.
  • Potassium bromide: KBr.
  • Aluminum sulfate: Al2(SO4)3.
  • Potassium phosphate: K3PO4.
  • Calcium iodide: CaI2.
  • Iron(II) sulfide: FeS.

Isotopes

• Isotopes have the same atomic number (number of protons) but differ in their mass number (number of protons + neutrons).
• Examples of isotopes:
  • Carbon-12: 6 protons, 6 neutrons, 6 electrons.
  • Carbon-13: 6 protons, 7 neutrons, 6 electrons.
  • Nitrogen-15: 7 protons, 8 neutrons, 7 electrons.

Ions

• Aluminum cation (Al+3): 13 protons, 14 neutrons, 10 electrons.
• Sulfur anion (S-2): 16 protons, 18 neutrons, 18 electrons.

Atomic Number and Mass Number

• Atomic number identifies the element.
• Mass number identifies the isotope within a certain type of element.

Introduction to Chemistry

• The periodic table is a fundamental tool in chemistry.

Atoms and Molecules

• Elements can be composed of atoms or molecules.
• A pure element consists of one type of atom.
• A compound consists of different types of atoms.
• Examples of molecules: hydrogen, oxygen, nitrogen, and fluorine.
• Examples of pure elements: zinc, iron, and aluminum.

Metals, Non-metals, and Metalloids

• Elements can be classified as metals, non-metals, or metalloids based on their properties.
• Metals tend to conduct electricity.
• Non-metals are insulators.
• Metalloids have intermediate properties.

Compounds

• Compounds can be classified as ionic or molecular.
• Ionic compounds consist of ions.
• Molecular compounds consist of molecules.
• Ionic compounds are typically formed between metals and non-metals.
• Molecular compounds are formed between non-metals.

Naming Compounds

• Molecular compounds are named based on the number of atoms of each element in the molecule.
• Ionic compounds are named based on the metal and non-metal ions.
• Roman numerals are used to indicate the charge on the metal ion.
• Polyatomic ions are ions that consist of multiple atoms, such as sulfate (SO42-) and hydroxide (OH-).

Examples of Compounds

• Sulfur trioxide (SO3) is a molecular compound.
• Carbon dioxide (CO2) is a molecular compound.
• Lithium bromide (LiBr) is an ionic compound.
• Potassium iodide (KI) is an ionic compound.
• Calcium oxide (CaO) is an ionic compound.
• Sodium sulfate (Na2SO4) is an ionic compound.

Important Concepts

• Valence electrons are the electrons in the outermost energy level of an atom.
• Oxidation states are the charge on an atom in a compound.
• Roman numerals are used to indicate the charge on a metal ion in an ionic compound.

Solving for Oxidation States

• To solve for Pb, set the equation equal to zero, considering the charge of oxygen (-2) and the total negative charge, which leads to the oxidation state of Pb being +4.

Naming Ionic Compounds

• Cu2SO4 is named copper(I) sulfate.
• The oxidation state of copper is +1, confirmed by two methods: equation method and ion method.

Writing Formulas of Compounds

• Molecular compounds: reverse the naming process.
• Ionic compounds: balance the charges of the ions.

Isotopes

• Isotopes have the same atomic number (number of protons) but differ in their mass number (number of protons + neutrons).
• Examples of isotopes: Carbon-12, Carbon-13, and Nitrogen-15.

Ions

• Aluminum cation (Al+3): 13 protons, 14 neutrons, 10 electrons.
• Sulfur anion (S-2): 16 protons, 18 neutrons, 18 electrons.

Atomic Number and Mass Number

• Atomic number identifies the element.
• Mass number identifies the isotope within a certain type of element.

Introduction to Chemistry

• The periodic table is a fundamental tool in chemistry.

Atoms and Molecules

• Elements can be composed of atoms or molecules.
• A pure element consists of one type of atom.
• A compound consists of different types of atoms.
• Examples of molecules: hydrogen, oxygen, nitrogen, and fluorine.
• Examples of pure elements: zinc, iron, and aluminum.

Metals, Non-metals, and Metalloids

• Elements can be classified as metals, non-metals, or metalloids based on their properties.
• Metals tend to conduct electricity.
• Non-metals are insulators.
• Metalloids have intermediate properties.

Compounds

• Compounds can be classified as ionic or molecular.
• Ionic compounds consist of ions.
• Molecular compounds consist of molecules.
• Ionic compounds are typically formed between metals and non-metals.
• Molecular compounds are formed between non-metals.

Naming Compounds

• Molecular compounds are named based on the number of atoms of each element in the molecule.
• Ionic compounds are named based on the metal and non-metal ions.
• Roman numerals are used to indicate the charge on the metal ion.
• Polyatomic ions are ions that consist of multiple atoms, such as sulfate (SO42-) and hydroxide (OH-).

Examples of Compounds

• Sulfur trioxide (SO3) is a molecular compound.
• Carbon dioxide (CO2) is a molecular compound.
• Lithium bromide (LiBr) is an ionic compound.
• Potassium iodide (KI) is an ionic compound.
• Calcium oxide (CaO) is an ionic compound.
• Sodium sulfate (Na2SO4) is an ionic compound.

Important Concepts

• Valence electrons are the electrons in the outermost energy level of an atom.
• Oxidation states are the charge on an atom in a compound.
• Roman numerals are used to indicate the charge on a metal ion in an ionic compound.

Solving for Oxidation States

• To solve for Pb, set the equation equal to zero, considering the charge of oxygen (-2) and the total negative charge, which leads to the oxidation state of Pb being +4.

Naming Ionic Compounds

• Cu2SO4 is named copper(I) sulfate.
• The oxidation state of copper is +1, confirmed by two methods: equation method and ion method.

Writing Formulas of Compounds

• Molecular compounds: reverse the naming process.
• Ionic compounds: balance the charges of the ions.

Isotopes

• Isotopes have the same atomic number (number of protons) but differ in their mass number (number of protons + neutrons).
• Examples of isotopes: Carbon-12, Carbon-13, and Nitrogen-15.

Ions

• Aluminum cation (Al+3): 13 protons, 14 neutrons, 10 electrons.
• Sulfur anion (S-2): 16 protons, 18 neutrons, 18 electrons.

Atomic Number and Mass Number

• Atomic number identifies the element.
• Mass number identifies the isotope within a certain type of element.