Intro to Atoms and Subatomic Particles

A set of vocabulary-style flashcards covering key concepts from the video notes: atoms, subatomic particles, isotopes, ions, notation, allotropy, graphite, diamond, formulas, and basic notation.

Atom

The basic building block of matter, composed of a nucleus (protons and neutrons) surrounded by electrons.

Subatomic particles

The three fundamental particles of an atom: protons (positive, in the nucleus), neutrons (neutral, in the nucleus), and electrons (negative, around the nucleus).

Proton

Positively charged subatomic particle located in the nucleus; relatively massive.

Neutron

Electrically neutral subatomic particle located in the nucleus; contributes to mass.

Electron

Negatively charged subatomic particle surrounding the nucleus; very small mass and determines the atom’s volume.

Nucleus

Center of the atom where protons and neutrons reside; contains most of the atom’s mass.

Atomic number

The number of protons in an atom; defines the element and is shown as the integer on the periodic table.

Mass number

The total number of protons and neutrons in an atom; used to identify isotopes.

Isotope

Atoms of the same element with different numbers of neutrons; same protons, different mass numbers.

Ion

An atom with a net electric charge due to loss or gain of electrons (cation if positive, anion if negative).

Atomic mass

The decimal average mass of an element’s atoms, reflecting isotopic abundances.

Isotope notation

A representation using a superscript (mass number) and a subscript (atomic number) with the symbol to specify a particular isotope.

Carbon-14

An isotope of carbon with a mass number of 14 (6 protons and 8 neutrons).

Allotropy

Different structural forms of the same element; for carbon, graphite and diamond are allotropes.

Graphite

Layered form of carbon where each carbon bonds to three others; strong in-layer bonds and weak interlayer bonds, used in pencils.

Diamond

Another allotropic form of carbon with a different covalent network; very hard.

Chemical formula

A formula using element symbols and subscripts to show how many atoms of each element are in a compound.

Sodium chloride (NaCl)

Common table salt; compound formed from sodium and chloride ions; represented by the formula NaCl.

Scientific notation

A compact way to write very large or very small numbers using powers of ten, e.g., 6 x 10^23.

Electron energy levels

Electrons occupy energy shells; closer to the nucleus means lower energy and stronger attraction; farther away means higher energy.

Molar mass

The mass of one mole of a substance, derived from atomic masses and isotopic composition; used in stoichiometry.

Periodic table basics

Atomic number is the integer on the table; atomic mass is the decimal; columns (groups) indicate similar properties.

Isotope abundance and atomic mass

Atomic mass is the decimal average of an element’s isotopes, weighted by their natural abundances.