Atomic Structure, Periodic Table, and Chemical Bonding

Flashcards covering key vocabulary and concepts from the lecture notes on atomic structure, the periodic table, and chemical bonding.

Atom

The smallest unique part of an object; in Greek, "Atomos" means indivisible.

Element

Materials made up of the same type of atom.

Proton

A subatomic particle found in the nucleus with a slightly positive charge and a mass of approximately 1 atomic mass unit.

Neutron

A subatomic particle found in the nucleus with a neutral charge and a mass of 1 atomic mass unit.

Electron

A subatomic particle that orbits the nucleus in electron shells, has a negative charge, and a tiny mass amount (~0).

Atomic Number (Z)

The number of protons in the nucleus of an atom. Every element has a unique atomic number.

Mass Number (A)

The total number of protons and neutrons in the nucleus of an atom.

Atomic Mass

The weight of one atom of an element in atomic mass units; it is approximately equal to the number of protons plus the number of neutrons.

Electron Shells

Electrons arrange themselves around the nucleus in shells. The maximum number of electrons in a shell follows the formula 2n^2, where n is the shell number.

Valence Electrons

Electrons in the outermost shell of an atom; these electrons are involved in chemical reactions.

Ion

An atom or molecule with an electrical charge due to the loss or gain of electrons.

Cation

A positively charged ion formed when an atom loses electrons (Metals lose electrons).

Anion

A negatively charged ion formed when an atom gains electrons (Non-metals gain electrons).

Valency

The charge of an ion.

Group (Periodic Table)

A column of elements in the periodic table; elements in the same group have similar chemical properties due to having the same number of valence electrons.

Period (Periodic Table)

A row of elements in the periodic table; the period number indicates the number of electron shells that the element has.

Metals

Elements that are typically lustrous, malleable, ductile, good conductors of heat and electricity, and solid at room temperature (except for mercury).

Non-metals

Elements that are typically dull, brittle, poor conductors of heat and electricity, and often gases or liquids at room temperature.

Alkali Metals

Elements in Group 1 of the periodic table; they are the most reactive metals and have one valence electron.

Alkaline Earth Metals

Elements in Group 2 of the periodic table; they have two valence electrons and are less reactive than alkali metals.

Halogens

Elements in Group 17 of the periodic table; they have 7 valence electrons and readily react to gain one electron.

Noble Gases

Elements in Group 18 of the periodic table; they have a complete outer shell of electrons, making them stable and inert (non-reactive).

Metallic Bonding

Bonding between two metals where electrons are delocalized and free to move.

Ionic Bonding

Bonding between a metal and a non-metal where electrons are transferred, forming ions that are attracted to each other.

Covalent Bonding

Bonding between two non-metals where electrons are shared.

Octet Rule

The tendency of elements to form bonds in order to achieve a full outer shell of 8 electrons (octet configuration).

Isotopes

Atoms of the same element that have different numbers of neutrons in their nuclei, resulting in different mass numbers.

Relative Abundance

The percentage of a particular isotope in a naturally occurring element.

Relative Atomic Mass (RAM)

The weighted average of the masses of all the isotopes of an element, measured in atomic mass units (amu).

Relative Isotopic mass (RIM)

Is the mass of an atom relative to the carbon-12 isotope.

Relative Molecular Mass

The sum of the relative atomic masses of all the atoms in a molecule or compound, measured in atomic mass units (amu).