Honors Chemistry Unit 1

Flashcards covering key vocabulary and concepts related to atomic structure, including atomic composition, mass spectrometry, moles, electron configuration, periodic trends, and photoelectron spectroscopy.

Atom

The smallest unit of matter consisting of protons, neutrons, and electrons.

Ion

An atom or molecule that has gained or lost electrons, resulting in a positive (cation) or negative (anion) charge.

Isotope

Forms of the same element with different numbers of neutrons, leading to different atomic masses.

Mass Spectrometry

A technique used to determine the isotopic composition and atomic mass of a sample by measuring the mass-to-charge ratio of ions.

Mole

A unit of measurement representing 6.022 × 10^23 particles (Avogadro's number) of a substance.

Molar Mass

The mass of one mole of a substance, typically expressed in grams per mole (g/mol) and found on the periodic table.

Aufbau Principle

Electrons first fill the lowest energy levels.

Pauli Exclusion Principle

States that no two electrons in an atom can have the same set of four quantum numbers.

Hund's Rule

Every orbital in a subshell is singly occupied with one electron before any one orbital is doubly occupied, and all electrons in singly occupied orbitals have the same spin.

Valence Electrons

Electrons in the outermost shell of an atom that are responsible for the chemical behavior of the atom.

Atomic Radius

Typically decreases across a period (→) and increases down a group (↓) in the periodic table.

Ionization Energy

Typically increases across a period (→) and decreases down a group (↓) in the periodic table.

Electronegativity

Typically increases across a period (→) and decreases down a group (↓) in the periodic table.

Photoelectron Spectroscopy (PES)

A technique that measures the energy needed to remove electrons from a substance. Higher binding energy indicates electrons closer to the nucleus.