An atom is defined as the smallest unit of an element that still retains its chemical properties. It consists of a nucleus made of protons and neutrons with electrons orbiting around it.

The identity of an element is determined by its number of protons, which is also known as the atomic number. This fundamental characteristic differentiates one element from another.

Electrons are the subatomic particles that carry a negative charge, while protons are positively charged and neutrons have no charge. This characteristic is essential for understanding basic atomic structure.

Water is composed of two hydrogen atoms bonded to one oxygen atom, which gives it the formula H2O. This is one of the most basic and well-known chemical compounds.

The periodic table is organized by increasing atomic number, which corresponds to the number of protons in an element's nucleus. This arrangement reveals periodic trends in chemical properties.

For a neutral atom, electrons and protons are present in equal numbers to balance the electrical charge. This balance is what keeps the atom electrically neutral.

An element is a pure substance that consists of only one kind of atom. Its atoms have identical numbers of protons, which defines the element's chemical identity.

The chemical symbol 'Na' is derived from the Latin name 'Natrium' for sodium. Recognizing element symbols is crucial for understanding chemical formulas in reactions.

Isotopes are atoms of the same element that have identical numbers of protons but different numbers of neutrons. This difference does not usually affect chemical properties but does affect atomic mass.

The atomic number is defined as the number of protons in an element's nucleus. It is a fundamental property that distinguishes one element from another.

A covalent bond is formed when atoms share pairs of electrons. This bonding type is essential for the structure of many molecules and plays a key role in organic chemistry.

Double displacement reactions involve the exchange of ions between reacting substances, usually in an aqueous solution. This type of reaction often results in the formation of a precipitate.

The formula weight is calculated by adding together the atomic weights of all atoms present in the compound's formula. This value is crucial for performing stoichiometric calculations in chemical reactions.

Electrons have a very small mass compared to protons and neutrons, making their contribution to the overall atomic mass minimal. This concept is often used to simplify calculations in atomic mass determinations.

Stoichiometry involves quantitative calculations that determine the amounts of reactants and products in a chemical reaction. It is a fundamental tool used to balance equations and predict yields.

The law of conservation of mass states that mass is conserved in a chemical reaction, meaning the total mass of the reactants equals the total mass of the products. This principle is fundamental in balancing chemical equations.

A neutral atom has an equal number of protons and electrons. Therefore, if the atom has 15 protons, it must also have 15 electrons to maintain electrical neutrality.

Elements in the same group possess similar valence electron configurations, which largely determine their chemical behavior. This similarity leads to trends in reactivity and bonding properties among group members.

The mole is a unit in chemistry that represents a specific number of particles, allowing scientists to count atoms or molecules in a sample. This concept is essential for converting between the mass of a substance and the number of particles it contains.

The coefficients in a balanced chemical equation specify the mole ratio of the reactants and products, ensuring that the number of atoms for each element is the same on both sides of the equation. This balance is critical for upholding the law of conservation of mass.