CHEM 1315: Unit 1 - Matter, Atoms, Elements and Particles

These flashcards cover essential vocabulary and principles related to matter, atomic structure, and basic chemistry concepts as discussed in the lecture.

Proton

A positively charged subatomic particle found in the nucleus of an atom.

Neutron

A neutral subatomic particle found in the nucleus of an atom, contributes to the mass number.

Electron

A negatively charged subatomic particle that orbits the nucleus of an atom.

Atomic Number (Z)

The number of protons in the nucleus of an atom, which determines the identity of the element.

Atomic Mass

The weighted average mass of the isotopes of an element, typically expressed in atomic mass units (amu).

Mole

A unit in chemistry that represents 6.022 x 10^23 particles, atoms, or molecules of a substance.

Isotope

Atoms of the same element that have the same number of protons but different numbers of neutrons.

Cation

A positively charged ion formed when an atom loses one or more electrons.

Anion

A negatively charged ion formed when an atom gains one or more electrons.

Diatomic Molecule

A molecule composed of two atoms, either of the same or different chemical elements.

Compound

A substance formed when two or more elements are chemically bonded together in fixed proportions.

Homogeneous Mixture

A mixture that has a uniform composition throughout.

Heterogeneous Mixture

A mixture that consists of visibly different substances or phases.

Periodic Law

The law stating that the properties of elements are periodic functions of their atomic numbers.

Kinetic Molecular Theory

Theory that describes the behavior of matter in terms of particles in motion, emphasizing the role of temperature and pressure.

Law of Conservation of Mass

A fundamental principle of classical physics that states that mass cannot be created or destroyed in a closed system.

Law of Definite Proportions

A chemical compound will always contain its component elements in fixed ratio by mass.

Law of Multiple Proportions

When two elements combine to form different compounds, the ratios of the masses of one element that combine with a fixed mass of the other are simple whole-number ratios.