CHEM 154 DEFINITION TERMS

CHEM 154 DEFINITION TERMS

core electrons - ✔✔The electrons that are not in the outermost shell of an atom



valence electrons - ✔✔Electrons on the outermost shell, which for chemical bonds



cation size - ✔✔Smaller than neutral atom due to less electrons which are pulled closer by the nucleus



anion size - ✔✔larger than neutral atom



isoelectronic - ✔✔same number of electrons, the more negative a species is, the greater its size



Effective nuclear charge (Zeff) - ✔✔the actual nuclear charge experienced by an electron, atoms further
from the nucleus experience less attraction due to shielding



Zeff Trend - ✔✔increases up and to the right



Ionization energy - ✔✔The amount of energy required to remove an electron from an
atom/molecule/ion in a gaseous state



Ionization energy trend - ✔✔increases up and to the right



Electron affinity - ✔✔the energy change that occurs when an electron is acquired by a neutral atom in a
gaseous state



Electron affinity trend - ✔✔increases up and to the right (more negative)



Electronegativity (EN) - ✔✔the relative ability of a bonded atom to attract shared electrons, calculated
value