The Periodic Law Flashcards
Dmitri Mendeleev
Russian chemist
developed and published the first periodic table of the elements
predicted the discovery of several new elements
Mendeleev’s periodic table
organized by increasing atomic mass
showed repeating (periodic) properties in columns
not perfect but highly accurate
Henry Moseley
English physicist
discovered that the elements in the periodic table fit into patterns better when they were arranged in increasing order according to the number of protons than by atomic mass
led to the definition of atomic number
rearranged the periodic table by atomic number
discovered the periodic law
periodic law
states that the physical and chemical properties of the elements are periodic functions of their atomic numbers
periodic table
an arrangement of the elements in order of their atomic numbers so that elements with similar properties fall in the same column

groups
families
vertical columns on the periodic table
information given by groups
number of valance electrons in elements
quantum numbers given by groups
angular momentum quantum number
magnetic quantum number
spin quantum number
range of groups
1 to 18
periods
horizontal rows on the periodic table
information given by periods
number of energy levels in elements
quantum number given by periods
principal quantum number
range of periods
1 to 7
blocks
4 regions of the periodic table containing elements based on the electron configurations of elements
determination of blocks on periodic table
sublevel being filled in successive elements of that block
quantum number given by blocks
angular momentum quantum number
range of blocks
s
p
d
f
s-block
group 1 and group 2 on the periodic table

p-block
group 13 through group 18 on the periodic table

d-block
group 3 through group 12 on the periodic table

f-block
lanthanides series and actinide series on the periodic table

main group elements
s-block elements and p-block elements
general valence electron configuration of group 1
ns1
general valence electron configuration of group 2
ns2
general valence electron configuration of group 3
ns2(n-1)d1
general valence electron configuration of group 4
ns2(n-1)d2
general valence electron configuration of group 5
ns2(n-1)d3
general valence electron configuration of group 6
ns1(n-1)d5
general valence electron configuration of group 7
ns2(n-1)d5
general valence electron configuration of group 8
ns2(n-1)d6
general valence electron configuration of group 9
ns2(n-1)d7
general valence electron configuration of group 10
ns2(n-1)d8
general valence electron configuration of group 11
ns1(n-1)d10
general valence electron configuration of group 12
ns2(n-1)d10
general valence electron configuration of group 13
ns2np1
general valence electron configuration of group 14
ns2np2
general valence electron configuration of group 15
ns2np3
general valence electron configuration of group 16
ns2np4
general valence electron configuration of group 17
ns2np5
general valence electron configuration of group 18
ns2np6
types of periodicity
atomic radii
ionic radii
ionization energy
electron affinity
electronegativity
shielding effect
chemical reactivity
cation
positively charged ions
formed by the loss of all valence electrons in an element
made from atoms of metals
oxidation
loss of electrons
anions
negatively charged ions
formed by gaining enough electrons to obtain a noble gas configuration
made from atoms of nonmetals
reduction
gain of electrons
atomic radii
distance from the center of the nucleus of an atom to the border of the electron cloud
found by calculating half of the distance between the nuclei of identical atoms that are bonded together because there is no definite border of the electron cloud

periodic trends of atomic radii
decreases from left to right
increases from top to bottom

ionic radii
distance from the center of the nucleus of an ion to the border of an electron cloud
ionic radii of cations (in comparison to an atom)
smaller than the atomic radius of a neutral atom due to loss of electrons
ionic radii of anions (in comparison to an atom)
larger than atomic radius of a neutral atom due to gain of electrons
periodic trends of ionic radii
decreases from left to right
increases from top to bottom

ionization energy (IE)
amount of energy (in kJ/mol) needed to remove 1 electron from a neutral atom
nth ionization energy (IEn)
energy (in kJ/mol) needed to remove an atom’s nth electron after the (n-1) electrons removed before it
periodic trends of ionization energy
increases from left to right
decreases from top to bottom

electron affinity (EA)
release of energy that occurs when an electron is acquired by a neutral atom
periodic trends of electron affinity
increases from left to right
decreases from top to bottom

reason for electron affinity of last group of each block to be equal to zero
final group of each block has filled all orbitals but new orbitals cannot be built for anions
significance of a negative electron affinity value
represents amount of energy released
does not represent a negative measurement (not possible)
electronegativity
a measure of the ability of an atom in a chemical compound to attract electrons
based upon the arbitrarily assigned value of 4.0 to fluorine (most electronegative element)
periodic trends of electronegativity
increases from left to right
decreases from top to bottom

shielding effect
ability of inner electrons to pull on valence electrons
periodic trends of shielding effect
constant from left to right
increases from top to bottom
Jöns Jacob Berzelius
Swedish chemist
chose to use Latin to name the elements so that there was a unified name in a language that everybody understood
decided to give metals symbols with 2 letters
decided to give nonmetals symbols with 1 letter
Stanislao Cannizzaro
Italian chemist
presented a convincing method for accurately measuring the relative masses of atoms
enabled chemists to agree on standard values for atomic mass and other properties of the elements