Mass Spectroscopy and Atomic Structure

Flashcards covering key concepts from mass spectroscopy, atomic structure, and electronic configuration.

Atomic mass units (amu)

A unit of mass used to express the mass of individual atoms or molecules, defined relative to carbon-12.

Avogadro's number

The constant 6.022 × 10^23 mol^-1 that represents the number of particles in one mole of a substance.

Constituent particles

The individual atoms, molecules, or ions that make up a substance.

Dimensional analysis

A mathematical technique for converting between different units of measurement by using conversion factors.

Formula unit

The smallest unit of a compound that shows the fixed proportions of atoms or ions held together.

Molar mass

The mass in grams of one mole of a substance, numerically equal to the average mass of one particle in atomic mass units.

Mole concept

A fundamental chemistry concept relating the number of particles to measurable quantities through Avogadro's number.

Average atomic mass

The weighted average of the masses of all isotopes of an element, based on their relative abundances.

Isotopes

Atoms of the same element that have different numbers of neutrons and therefore different mass numbers.

Mass spectrum

A graphical representation showing the masses of isotopes of an element and their relative abundances.

Relative abundance

The percentage or proportion of each isotope present in a naturally occurring sample of an element.

Weighted average

A calculation method that accounts for the relative abundance of each isotope in determining the average atomic mass.

Elemental composition by mass

The percentage or proportion of each element present in a substance, expressed as a mass fraction or mass percentage.

Empirical formula

The chemical formula that represents the lowest whole number ratio of atoms of the elements in a compound.

Law of definite proportions

The principle that the ratio of the masses of constituent elements in a pure sample of a compound is always the same.

Purity

The degree to which a substance contains only one type of atom without contamination.

Aufbau principle

The rule that electrons fill orbitals in order of increasing energy.

Coulomb's law

The principle that the electrostatic force between charged particles is proportional to the product of their charges.

Effective charge

The net positive charge experienced by an electron, accounting for shielding by inner electrons.

Ionization energy

The energy required to remove an electron from an atom in the gas phase.

Valence electrons

Electrons in the outermost shell of an atom that participate in bonding.

Periodic trends

Recurring patterns of properties in elements that vary predictably across the periodic table.

Electron affinity

The energy change that occurs when an electron is added to an atom.

Electronegativity

A measure of an atom's ability to attract valence electrons in a chemical bond.

Ionic radius

The size of an ion, differing from the neutral atom due to the gain or loss of electrons.

Chemical bond

An attractive force between atoms that holds them together in a compound.

Ionic compound

Compounds formed by the electrostatic attraction between cations and anions.

Reactivity

The tendency of an element to undergo chemical reactions and form bonds with other elements.