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Chemistry Set 2
Atoms
Term | Definition |
---|---|
anion | An ion with a negative charge, formed by gaining electrons. |
atom | The basic unit of matter, consisting of a nucleus (protons and neutrons) and electrons orbiting around it. |
atomic mass | The mass of an atom, expressed in amu. |
atomic number | The number of protons in an atom's nucleus, defining the element. |
atomic radius | The size of an atom, typically measured as the distance from the nucleus to the outermost electron shell. |
atomic symbol | A shorthand notation for an element, usually one or two letters. |
atomic weight | The average mass of an atom of an element, taking into account isotopic abundances. |
Aufbau principle | Electrons fill the lowest energy orbitals first before moving to higher energy ones. In other words, electrons enter orbitals in order of increasing energy. |
cation | An ion with a positive charge, formed by losing electrons. |
chemical formula | A representation of a chemical compound using symbols and subscripts to indicate the ratio of atoms. |
core electrons | Electrons in an atom that are not in the outermost shell. |
electron | A negatively charged subatomic particle that orbits the nucleus of an atom. |
electron cloud | A visual representation of the probability of finding an electron in a particular region around the nucleus. |
electron configuration | The distribution of electrons in the electron shells of an atom. |
electron distribution | The arrangement of electrons in an atom's electron shells. |
element | A substance composed of atoms with the same atomic number, representing a unique type of matter. |
filled shell | An electron shell that is completely filled with electrons. |
Hund's Rule | Dictates that electrons occupy orbitals of the same energy level in a way that maximizes the number of unpaired electrons. |
ion | A charged particle formed by gaining or losing electrons. |
isotope | Atoms of the same element with different numbers of neutrons and therefore different atomic masses. |
molar mass | The mass of one mole of a substance, expressed in grams per mole. |
net charge | The overall charge of an ion, calculated by subtracting the number of electrons from the number of protons. |
neutron | A neutral subatomic particle found in the nucleus of an atom. |
nucleus | The central part of an atom, containing protons and neutrons. |
orbitals | Regions in an atom where electrons are likely to be found. s, p, d, and f varieties |
Pauli Exclusion Principle | States that no two electrons in an atom can have the same set of four quantum numbers. It implies that each orbital can hold a maximum of two electrons with opposite spins. |
proton | A positively charged subatomic particle found in the nucleus of an atom. |
pure substance | A substance composed of only one type of atom or molecule. |
shielding | The reduction in the attractive force between an electron and the nucleus due to inner-shell electrons. |
valence electrons | Electrons in the outermost shell of an atom, involved in chemical bonding. |
valence shell | The outermost electron shell of an atom. |