L2 - Atomic Structure and Moles

Flashcards covering atomic structure, physical vs. chemical changes, representing reactions and quantities in chemistry.

Diatomic

Indicates that there are two atoms of that element bonded together (e.g., O2).

Coefficient

Indicates the number of molecules of a substance that react in a chemical reaction.

Physical Change

A change where the chemical composition of a substance remains the same; involves changes in state or appearance.

Physical Change

A change where no chemical bonds are broken or formed; the substance remains chemically the same.

Chemical Change:

A change that requires the breaking and formation of chemical bonds.

Boiling

Liquid to a gas.

Condensation

Gas to a liquid.

Melting

Solid to a liquid.

Freezing

Liquid to a solid.

Sublimation

Solid directly to a gas.

Deposition

Gas directly to a solid.

Allotrope

Different forms of the same element with different arrangements, leading to different properties.

Physical Properties

Color, melting point, conductivity, density, surface tension; do not involve a change in chemical nature.

Chemical Properties

Properties that relate to a change in the chemical structure; involves breaking and forming bonds.

Flammability

The ability of a substance to catch fire and combust, breaking and forming bonds.

Corrosiveness

The ability of a substance to react and break down bonds, forming new bonds elsewhere. Eg. Iron + Water → Iron Oxide (Rust)

Distillation

The process of boiling off a substance and collecting it separately, without chemically changing it.

Protons

Positively charged particles in the nucleus of an atom.

Neutrons

Neutral particles in the nucleus of an atom.

Electrons

Negatively charged particles orbiting the nucleus of an atom.

Nucleons

Protons and neutrons within the nucleus of an atom.

Element Identity

Determined by the number of protons in its nucleus.

Atomic Number (Z)

The number of protons in an atom's nucleus, defining the element.

Isotopes

Atoms with the same number of protons but different numbers of neutrons, leading to variations in mass.

Mass Number

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

Cations

Positively charged ions formed when an atom loses electrons.

Anions

Negatively charged ions formed when an atom gains electrons.

Atomic Mass Unit (AMU)

A unit to express the relative masses of atoms and molecules

Mole

A universal unit to count the number of objects, items, or particles.

Avogadro's Number (NA)

6.022 x 10^23 particles in one mole.

Molar Mass

The mass of one mole of a substance, typically expressed in grams per mole (g/mol).