An atom is the basic building block of matter and retains the chemical properties of an element. It is not a large collection of molecules or a chemical reaction.

Protons carry a positive charge and are located in the nucleus along with neutrons. Electrons carry a negative charge and orbit the nucleus.

Neutrons are located in the nucleus with protons and help stabilize the atomic nucleus. Electrons orbit the nucleus and carry a negative charge.

Elements in the periodic table are arranged in order of increasing atomic number, which reflects the number of protons in the nucleus. Atomic mass is similar but not the primary ordering criterion.

Water is composed of two hydrogen atoms and one oxygen atom, represented by the formula H2O. The other formulas describe different compounds.

The law of conservation of mass asserts that mass remains constant in a chemical reaction, meaning no mass is lost or gained. This principle is vital for balancing chemical equations.

A balanced chemical equation requires that the number of atoms for every element is identical on both sides of the reaction. This ensures that the law of conservation of mass is met.

Covalent bonds occur when two atoms share one or more pairs of electrons to achieve stability. This is contrasted with ionic bonds, where electrons are transferred rather than shared.

The key difference is that ionic bonding involves the transfer of electrons to form oppositely charged ions, while covalent bonding is characterized by the sharing of electrons between atoms. This distinction influences the properties of the resulting compounds.

Stoichiometric calculations rely on a balanced chemical equation to determine the quantitative relationships among reactants and products. Accurate balancing ensures that the conservation of mass is maintained.

Electrons, particularly those in the outer electron shells, are involved in forming chemical bonds. Their sharing or transfer between atoms results in covalent or ionic bonds, respectively.

Across a period, the effective nuclear charge increases, drawing electrons closer to the nucleus and reducing the atomic radius. This trend is one of the periodic properties observed in the periodic table.

In redox reactions, the oxidizing agent accepts electrons, and is thereby reduced. Meanwhile, the reducing agent loses electrons, undergoing oxidation.

Molarity is defined as the moles of solute present in one liter of solution, making it a key concept for determining solution concentration. It is essential in various quantitative analyses in chemistry.

A catalyst works by lowering the activation energy of a reaction, thereby increasing its rate without being consumed in the process. It does not alter the reaction's equilibrium position.

For exothermic reactions, decreasing the temperature causes the equilibrium to shift toward the product side to produce more heat. This is consistent with Le Chatelier's principle, which predicts the system will adjust to counteract the change.

A molecule with four bonding pairs and no lone pairs adopts a tetrahedral geometry to minimize electron pair repulsion. This arrangement results in bond angles of approximately 109.5°.

The energy required to convert a liquid into a gas is called the heat of vaporization. This concept is critical in understanding phase changes and the energy involved in such transitions.

The electron configuration corresponds to an element with 16 electrons, which is sulfur. Sulfur is located in Group 16 of the periodic table, also known as the chalcogens.

Bond polarity arises from differences in electronegativity between atoms, where a larger difference creates a stronger dipole moment. This results in a polar bond as electrons are unequally shared.