Periodic Trends
What is the Octet Rule?
Atoms react by gaining or losing electrons so as to acquire the stable electron configuration of a noble gas, usually 8 valence shell electrons. Exception: Helium with a duet (2).
why?
Higher energy levels have larger orbitals
Why is the anion larger than the neutral atom of that element?
It has gained electrons which prevents the protons, that remain the same, from pulling them in as much.
Why is a cation smaller than the neutral atom of that element?
It has lost electrons enabling the remaining electrons to be pulled in closer by the nuclear charge.
Rank the following elements by increasing electronegativity: sulfur, oxygen, neon, aluminum.
Neon, Aluminum, Sulfur, Oxygen
Rank the following elements by increasing atomic radius: carbon, aluminum, oxygen, potassium.
Oxygen, carbon, Aluminum, Potassium
Both sodium and chlorine are in the same period on the periodic table. Which atom is larger? Why?
Sodium, because the nuclear charge increase left to right pulling electrons closer in chlorine.
electronegativity
a measure of the ability of an atom in a chemical compound to attract electrons
how does it decrease and increase?
decrease going down, increase going up
valence electrons
electrons on the outermost energy level of an atom
how does ionization increase?
increase UP and RIGHT
What happens to ionization energy when moving across a period?
increases because of increased nuclear charge
how does atomic radius increase?
increases to the LEFT and DOWN
The energy required to remove an electron from an atom is defined as
ionization energy
what happens to electronegativity when it moves down a group
it decreases
What happens to electronagativity when moving -> across a period
it increases
Ionization energy
the amount of energy required to remove an electron from an atom
nuclear charge
the charge of the nucleus equal to the number of protons
the larger the atom
the more loosely its electrons hold on
shielding effect
the reduction of the attractive force between a nucleus and its outer electrons due to the blocking effect of inner electrons
