CHEM 101 Unit 1 - Atomic Structure (Terms)

Matter

Anything with mass and volume

Pure Substance

Material with constant composition properties, made up of only one substance

Element

A pure substance composed of only one type of atom

Compound

A pure substance composed of whole number ratios of two or more types of atoms

Billiard Ball Atomic Model

The atomic model stating that atoms are the smallest, indivisible component of matter that makes up all material

Plum Pudding Atomic Model

The atomic model stating that electrons are randomly dispersed throughout positive matter because there must be positive charge to offset the negative charge of the electrons (neutral atom)

Nuclear Atomic Model

The atomic model stating that there is a positively charged nucleus in the middle of the atom and that electrons reside in otherwise empty space

Isotope

Atoms of the same element (same number of protons) but different number of neutrons

Ion

An atom or group of atoms that carries a net positive or negative charged, formed due to an element’s electron affinity

Ionic Compound

Compounds made up of a metal and nonmetal monatomic ion or two or more polyatomic ions

Binary Compound

A type of covalent compound made up of two nonmetals

Acid

A type of covalent compound made up of at least one hydrogen atom that produces hydronium ions when in water

Binary Acid

An acid that does not contain oxygen (composed of only H and a nonmetal/polyatomic ion)

Oxyacid

An acid containing oxygen (composed of H and oxoanion)

Oxoanion

Polyatomic ion with general formula XO_n^-

Wavelength

The distance between two consecutive waves/troughs (distance travelled during one full cycle)

Frequency

Number of complete cycles that pass a given point per second

Speed

The distance propagated by a wave per unit of time (c = 3 ×10⁸)

Quantum

The smallest amount of energy (discrete packet) that can be absorbed or emitted in the form of electromagnetic radiation

Photoelectric Effect

A phenomenon in which metal surfaces exposed to monochromatic light cause electrons to be ejected

Emission Spectrum

When a sample of gaseous atoms that absorbs light and releases some of it back in the form of light, forming a discontinuous spectrum with only a few bright lines

Bohr Model for One-Electron Species

An atomic model only applicable to one-electron species stating that electrons can only exist in specific orbits with quantized energy levels, and do not emit or absorb any radiation when in these levels

One Electron Species

Atoms with ionized electrons such that only one electron remains on the atom

Fractional Abundance

the fractional amount of a specific isotope that makes up a percentage of the total atomic mass

Heisenburg’s Uncertainty Principle

The principle stating that it is impossible to know simultaneously the position and momentum of a particle because the more accurately we measure the momentum of a particle, the less accurate its position will be

Wave Function

The probability density of an electron particle being present in a specific location

Principle Quantum Number (n)

Quantum number that defines the size, location, and energy of the orbital

Angular Momentum Number

Quantum number that describes the shape (type) of the orbital

Magnetic Quantum Number

Quantum number that refers to the 3-D orientation of the orbital in the space surrounding the nucleus

Electron Spin Quantum Number

Quantum number that describes the orientation of the electron occupying the orbital

Main Shell

Energy level (n value)

Subshell

Orbital type, organized by its l value (s, p, d, f)

Orbital

Orientation and space of a specific electron in a shell

Pauli’s Exclusion Principle

The principle stating that given orbital cannot contain two electrons with the same spin, meaning no two electrons can have the same 4 quantum numbers

Node

A region in which there is zero probability of finding an electron

Radial Node

The nodes found in s-orbitals that are circular and flat that are “slices” of a plane

Probability Density

The probability of finding an electron at a specific point in the atom

Radial Distribution

The probability of finding an electron at specific radius away from nucleus of an atom

Angular Nodal Plane

Nodes found in p and d-orbitals resembling an entire plane that separates phases of an orbital

Angular Nodal Cone

Node found in d_z² orbital shaped like a cone that separates the three phases of the orbital

Degenerate

A term describing orbitals that have the same amount of energy

Electron-Electron Repulsion

A phenomenon found in many-electron atoms in which electrons within and between orbitals repel each other, leading to decreased nuclear attraction

Shielding

The act of reducing the amount of nuclear attraction felt by an electron

Electron Penetration Energy

How close an electron in an orbital can get to the nucleus based on its radial probability distribution

Orbital Energy

The amount of energy contained in an orbital that directly correlates with the effective nuclear charge felt by its electrons

Effective Nuclear Charge

The amount of nuclear charge felt by an electron with shielding taken into account

Core Electrons

Any electrons in main shells between a given electron and the nucleus

Condensed Electron Configuration

Å way to notate electron configuration by substituting core electrons with a group 18 element (noble gas) and only showing the outer electrons

Hund’s Rule

A rule stating that the electron configuration with the least energy is the one in which, for a given set of degenerate orbitals, there is the highest possible number of unpaired electrons

Aufbau Principle

The principle stating that when an atom or ion is in its ground state, electrons fill the atomic orbitals of the lowest available energy levels before occupying higher energy levels

Ground State Electron Configuration

Filling electrons starting from the lowest energy orbital and progressively going up

S-Block Element

Elements that fill up the s-orbital of their main shell (group 1 and 2)

P-Block Element

Elements that fill up the p-orbital of their main shell (group 13-17)

Transition Element (D-Block Elements)

Elements that fill up the d-orbital of their main shell (group 3-12 starting from period 4)

Inner Transition Element (F-Block Element)

Elements that fill up the f-orbital of their main shell (between group 3 and 4 starting from period 6)

Lanthanides

Inner transition elements found on period 6

Actinides

Inner transition elements found on period 7

Atomic Size

The size of the atom based on its electron shells and nucleus size

Paramagnetic

A property of an element containing unpaired electrons in which the unpaired electrons create their own magnetic field, making the element magnetic

Diamagnetic

A property of an element containing no unpaired electrons in which the paired electrons make the element repelled by a magnetic field

Ionic Radius

The size of an ion based on the location of its outermost shell

Isoelectronic

A property describing ions that have the same electron number, but with different configurations

Ionization Energy

The minimum energy needed to remove an electron from a molecule in its gaseous state

Electron Affinity

The energy change that occurs when an electron is added to a gaseous atom or ion

Inert Electron Pair Effect

A phenomenon of p-block elements in which heavier elements of the group (down a group) have an increased tendency to keep their 2 s-orbital valence electrons

Metallic Behaviour

The ability of an element to have “metallic properties” 

Reducing Power

The ease at which a metal will give up its electron to reduce the other element in a redox reaction

Peroxide

A metal oxide with the formula M₂O₂ formed from a combination of a metal ion M⁺ and the peroxide ion O₂^2-

Superoxide

A metal oxide with the formula M₂O formed from a combination of a metal ion M⁺ and the superoxide ion O₂^2-

Oxidizing Power

The ease at which a halogen will receive valence electrons to oxidize the other element in a redox reaction

Halogen Displacement Reaction

Reactions that evaluate the relative oxidizing strength of halogens by reacting them with each other

Acidic Oxides

Oxides of nonmetals that produce hydronium ions when they react with water

Basic Oxides

Oxides of reactive metals that produce hydroxide ions when they react with water

Amphoteric Oxides

Oxides that have characteristics of both metals and nonmetals

Anhydrides

Substances that produce a base or an oxide (or have no reaction) when reacting with water

Water-Gas Shift Reaction

Treating coal (carbon) or carbon monoxide with steam (water gas) to create hydrogen gas and a carbon oxide

Steam Hydrocarbon Reforming

Treating a hydrocarbon with steam to create hydrogen gas and a carbon oxide

Ionic Hydride

A reactive metal bonded with hydrogen

Metallic/Interstitial Hydride

A solid-gas solution occurring when H atoms occupy the empty spaces (interstices) of the crystal structure of the transition metals

Haber Process

A reaction involving hydrogen used to produce ammonia

Hydrogenation of Vegetable Oils

A reaction of hydrogen in which double bonded carbon (unsaturated) react with hydrogen to become saturated (carbon with only single bonds)