Practical Chemistry
TEST Objectives/Notes:
Unit 6: ELECTRONS IN ATOMS
 Use a
periodic table to determine the correct number of protons,
neutrons, and electrons in a particular atom.
o Atomic # equals # protons and # electrons in an atom
o # Neutrons = Mass # minus # Protons
 Understand the electron configuration as given in the Periodic Table.
o Distinguish between ground and excited states.
 Label a Bohr diagram of an atom including the electron energy shells.
o Label the subatomic particles, their symbols, charges, mass, and location.
 Identify valence electrons and distinguish them from kernel electrons.
o Draw Lewis (Electron) Dot structures for atoms.
o Know the Octet Rule requiring no more than eight electrons in the valence shell.
o Kernel: includes the nucleus and all inner electron shell electrons (NOT valence).
 Distinguish between isotopes of an element; know isotopic notation.
o Remember, isotopes have the same atomic number! (But different # neutrons.)
o Isotopic Notation for carbon: C-12 or 126C.
 Distinguish between the
Bohr and the Orbital models of the atom.
o Term orbital indicates most likely location of an electron (probability).
o Each electron in an atom has a distinct amount of potential energy.
 Distinguish between
ground state and excited state configurations of an
atom.
o Use the electron configuration given in the Reference Table as the ground state.
o Ground State: electrons occupy their lowest possible energy level.
o Excited State: electrons occupy higher energy levels while lower levels are vacant.
 Define the term principal energy level.
o The principal energy level (n) is the number of energy levels as shown in the
electron configuration on the periodic table. Ex: carbon has a configuration of 2-4.
This means there are two principal energy levels, n=1 containing 2 electrons, and
n=2 containing 4 electrons.
 Explain the cause of
spectral lines in terms of electrons and energy
levels.
o State how Bright-Line spectra are produced in terms of energy states of an electron.
o Distinguish between continuous and bright-line spectra.
o Know that each element has its own unique bright-line spectrum.