UNIT 1: ATOMIC STRUCTURE & PROPERTIES

The periodic table gives you basic but important information about each element

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==Symbol== - The unique symbol that represents an element on the periodic table

==Atomic Number== - The number of protons located within the nucleus of an element. Also equal to the number of electrons surrounding the nucleus of a neutrally charged element.

==Molar Mass== - The average atomic mass of an atom and also the average mass per mol of the atom

==Periods== - the horizontal rows of the periodic table

==Groups== - the vertical columns of the periodic table

The two rows offset beneath the table are alternatively called the ==Lanthanides== (4f) and the ==Actinides== (5f): Rare Earth Metals or Inner Transition Metals.

==Mass Number== - The sum of an atoms protons and neutrons

==Isotopes== - Atoms of an element with different number of neutrons

==Avogadro’s Number== - The number of atoms that are in a single mole of any given element (6.022 x 10^23 particles)

==Molarity(M)== - moles of solute/liters of solution

==Empirical Formula== - The simplest ratio of one element to another in a compound

==Molecular Formula== - The actual formula for a substance

==Electrostatic Force== - the attraction between opposite charges

==Coulomb’s Law== - Force of attraction = q1q2/r^2. Measures the force of attraction between two charges.

==Energy Level== - fixed distances from the nucleus of an atom where electrons may be found (1-7)

==Subshells== - a subdivision of electron shells separated by orbitals (s, p, d, & f)

==Orbital== - the position surrounding an atom’s nucleus where electrons are most likely to be found at any given moment

==Electron Configuration== - the complete description of the energy level and subshell that each electron on an element inhabits

==Aufbau Principle== - when building up the electron configuration of an atom, electrons are placed in orbitals, subshells, and shells in order of increasing energy

==Pauli Exclusion Principle== - two electrons which share an orbital cannot have the same spin

==Hund’s Rule== - when an electron is added to a subshell, it will always occupy an empty orbital if one is available

==Valence Electrons== - the electrons in the outermost s and p subshells

==Atomic Radius== - the approximate distance from the nucleus of an atom to its valence electrons

==Ionization Energy== - the energy required to remove an electron from an atom

==Electronegativity== - how strongly the nucleus of an atom attracts the electrons of other atoms in a bond

==Electron Affinity== - the energy change that occurs when an electron is added to an atom in its gaseous state

==Effective Nuclear Charge== - the net attractive force of the nucleus on any given electron (approximately equal to the number of protons - core electrons)