Atomic Structure and the Periodic Table

Flashcards covering the fundamentals of atomic structure, periodic table trends, chemical bonding, and material structures based on the lecture notes.

Periodic table

A big chart that organizes the elements, puts similar ones next to each other, and arranges them by their atomic number; it is made up off 118 elemets.

Periods

The horizontal raws in the periodic table.

Groups

The vertical columns in the periodic table.

Neutrons

Particles with a neutral charge found within the atom.

Protons

Particles with a positive charge found within the atom.

Electrons

Particles with a negative charge that surround the nucleus; in a neutral atom, their number equals the number of protons.

Atomic number

The number that tells you the number of protons of the element; it increases by one with every element.

Mass number

The number that tells you the number of protons + neutrons of the element.

Density

The measure of the mass for a fixed volume of a substance, calculated using the formula $\text{Density} = \frac{\text{Mass}}{\text{Volume}}$, with the unit $g/cm^3$.

Rutherford’s model

A model of atomic structure proposing that negatively charged electrons surround the nucleus and orbit it like planets around the sun.

Electron shells

Also called energy levels, these are the regions around the nucleus where electrons move; the first shell holds up to two electrons, while the second and third hold up to eight.

Electronic structure

The arrangement of electrons in shells around the nucleus, such as 2,1 for a Lithium atom.

Electrostatic forces

The forces between positive protons and negative electrons that hold the electrons in place.

Alkali metals

Group 1 elements that are very reactive and must be stored under oil to keep air away; they include Lithium, Sodium, and Potassium.

Flame tests

A method to detect Alkali metal ions based on flame color: Lithium (Red), Sodium (Orange), and Potassium (Lilac).

Halogens

Group 7 elements, including fluorine, chlorine, and bromine; they are non-metals whose reactivity decreases as you go down the group.

Noble gases

Group 8 elements including helium, neon, and argon; they are inert gases with full outer electron shells.

Ion

An atom that becomes charged by losing or gaining electrons to achieve a stable, full outermost electron shell.

Ionic bond

A chemical bond formed by the attraction between a positively charged ion and a negatively charged ion, typically appearing when a metal reacts with a non-metal.

Covalent bond

A type of chemical bond where atoms of non-metals share pairs of electrons to fill their outermost electron shells.

Lattice

A giant structure formed by ions in a regular pattern, characteristic of ionic compounds like sodium chloride ($NaCl$).

Intermolecular forces

Weak forces between simple covalent molecules that account for their low melting and boiling points.

Macromolecules

Large structures, also known as giant covalent structures, formed by atoms joined by strong covalent bonds throughout the entire structure.

Diamond

A giant structure of carbon where each atom forms four strong covalent bonds in a rigid, three-dimensional lattice, making it the hardest material on Earth.

Graphite

A soft material made of carbon atoms arranged in layers that can easily slide over one another because the bonds between the layers are weak.