Physical Science -notes

flashcards covering key terms and definitions from the lecture notes on atomic structure, isotopes, ions, chemical bonding, radioactivity, periodic trends, mixtures, and solutions.

Isotopes

Atoms of the same element with the same number of protons but different numbers of neutrons, resulting in different atomic masses.

Atomic Mass Unit (amu)

A unit defined as 1/12th the mass of a carbon-12 atom, used to express atomic masses.

Carbon-12 standard

The carbon-12 atom used as the reference for atomic mass measurements.

Cations

Positively charged ions formed when an atom loses electrons.

Ions

Atoms or molecules with a net electrical charge due to loss or gain of electrons.

Compounds

Substances formed when two or more different elements are chemically bonded.

Atomic mass (definition)

The mass of an atom expressed relative to the carbon-12 standard.

Radioactive decay

Process by which an unstable nucleus loses energy by emitting radiation.

Electrons

Negatively charged subatomic particles located outside the nucleus.

Protons

Positively charged subatomic particles in the nucleus; define the element.

Neutrons

Electrically neutral subatomic particles in the nucleus; contribute to mass.

Nucleons

Protons and neutrons collectively; constituents of the nucleus.

Atomic number

Number of protons in the nucleus; unique identifier for an element.

Oxygen (example) atomic number

An atom with 8 protons has atomic number 8.

Electron cloud model

Quantum mechanical model where electrons occupy orbitals defined by probability.

Orbitals

Regions around the nucleus where electrons are likely found.

Molecules

Two or more atoms bonded together; the smallest unit of a compound that retains its properties.

Quarks

Fundamental constituents of protons and neutrons; held by the strong force.

Nucleon composition

Protons and neutrons are made of quarks; gluons mediate the strong force.

Half-life

Time required for half of a radioactive substance to decay; a characteristic constant.

Nuclear fission

Splitting of a nucleus into smaller parts, releasing energy and particles.

Salt-formers (halogens)

Group 17 elements that readily form salts with metals.

Halogens

Group 17 elements known as salt-formers.

Element

A substance that cannot be broken down into simpler substances by ordinary chemical means.

Copper family (Group 11)

Copper, silver, and gold; historically used for minting coins.

Atomic number and protons (Neon example)

Neon has atomic number 10, so a neutral neon atom has 10 protons.

Chemical formula

Concise notation showing the elements in a compound and their ratios (e.g., H2O).

Sodium chloride

Table salt; compound formed from sodium (Na) and chlorine (Cl).

Noble gases

Group 18 elements with full outer electron shells; very stable and unreactive.

Valence electrons

Electrons in the outermost shell that determine reactivity and bonding.

Sugar and water as compounds

Both sugar (sucrose) and water are compounds with fixed atomic ratios.

Solutions

Homogeneous mixtures; sugar in water is an example; components are solute and solvent.

Solute vs solvent

Solute is the substance dissolved; solvent is the substance doing the dissolving.

Solubility factors

Surface area and temperature affect dissolution rate; pressure affects gases; weight does not affect rate.

Heterogeneous vs Homogeneous mixtures

Heterogeneous: non-uniform; Homogeneous: uniform distribution.

Precipitate

A solid that forms and separates from a solution during a reaction.

Universal solvent

Water; dissolves more solutes than any other solvent.