Physical Science Flashcards
elements
each of 100+ substances that cannot be chemically interconverted or broken down into smaller substances and are primary constituents of matter.
each element is distinguished by atomic number.
compounds
A compound is a substance formed when two or more chemical elements are chemically bonded together
mixture
two or more substances which have been combined such that each substance retains its own chemical identity.
atom
the smallest component of an element; consists of neutrons, protons, and electrons
molecules
a group of atoms bonded together, representing the smallest fundamental unit of a chemical compound that can take part in a chemical reaction.
ions
an electrically charged atom or group of atoms; when the atom or molecule loses or gains 1 or more electrons
solids, liquids, gases
solids: definite shape, definite volume, molecules close and connected by intermolecular bonds
liquids: definite volume, no definite shape (take shape of container they’re in), molecules fairly close, weak intermolecular bonds
gases: no definite volume or shape, expand to fill the container, molecules far apart and moving freely, few intermolecular forces
atomic models
Dalton’s model: just one small object, didn’t not know about nucleus or electrons or anything like that
Thomson’s model: knew about smaller particles but not about the nucleus, thought negatively charge particles floated in positively charged “soup”
Rutherford’s model: introduced positively charged core (nucleus) with electrons that orbit the nucleus
Bohr’s model: introduced the levels of electrons
atomic structure
protons and neutrons are found in the nucleus, electrons orbit the nucleus in shells or orbitals
atomic number
the number of protons in the nucleus of the atom
atomic mass
the mass of the atomic particle, number of protons+neutrons
isotopes
atoms of the same element (same protons) with different numbers of neutrons
electron arrangements/valence electrons
electrons arranged in shells: 2 in first shell, 8 in second, 18 in third, etc.
valence electrons are the electrons associated w the atom and is available to participate in bonding to another atom. the electrons on the outside
radioisotopes
atoms that contain and unstable amount of neutrons and protons
radioactive decay processes and half-life
radioactive decay: the process by which the nucleus of an unstable atom loses energy by emitting radiation
half life: how quickly unstable atoms undergo decay and how long stable atoms survive decay