Studied by 6 peoplegrouped elements with similar properties first periodic table created by
Dmitri Mendeleev
who arranged periodic table together in order of increasing atomic number?
Henry Moseley
metals are located on which side of periodic table
left (exception:hydrogen)
characteristics of metals
-ductile -malleable good conductors of heat and electricity high melting points (except for Mercury)
nonmetals located on
right side of periodic table (C, P, S I ,Se=solids at room temp)
metalloids
staircase seperates nonmetals from metals
if element is a good conductor of heat but brittle it is
a metalloid
alkali metals melting point
-lowest melting point
which one can you cut w a knife?
alkali metals
moving down a group, metallic character becomes stronger for?
alkali metals and alkaline earth metals
alkaline earth metals melting point?
higher melting point than alkali metals
what is very reactive with water?
alkaline earth metals
what is the exception with reaction of water with these 2 elements?
Be=no reaction Mg= will react with steam
transition metals melting point is
high melting point and much less reactive than alkali metals
characteristics of transition metal
ductile and malleable
moving down group for transition metal, metallic character becomes
stronger
oxygen group metallic character increases going down or decreases
increases
O=
nonmetal
Te=
metalloid
Po=
metal
halogens are the most reactive...
nonmetals
which is the most reactive nonmetal for the halogens?
Flourine (F)
what is reactivity based on for halogens?
7 electrons in outer shell, wanting one more electron to fill octet
are noble gases reactive?
no because s and p shells are compeltely filled in
lanthinides
actinides are
metals, very reactive
are lanthinides or actinides radioactive?
actinides
Zeff is
charge experienced by an electron on a many-electron atom
going across periodic table, Zeff
increases
why does Zeff increase going across a period?
because more valence e- added while screening e- does not increase
going down periodic table, Zeff
increases slightly
put following elements in order of increasing Zeff: Be, Ca, Sr, Mg
Be<Mg<Ca<Sr
atomic radii across table
decreases
why does atomic radius decrease going across table?
bc as more e- added, nucleus pulls those e- closer, decreasing atom size
going down table, atomic radius
increases
why does atomic radius increase going down periodic table?
bc more shells added going down, increasing atom size
put elements in order of increasing atomic radius: Be, C, K, Ca
C<Be<C<K
Ionization energy is
energy required to remove one e- from a neutral atom of element
when e- removed or gained we create an
ion
across table IE
increases
why does IE increase across table?
bc more energy is required to remove e-
going down table, IE
decreases
why does IE decrease going down table?
bc less energy required to remove an e- bc they are farther from the nucleus
removing more e-, increases or decreases IE?
increases
put following elements in order according to IE: Be, C, K, Ca
K<Ca<Be<C
Electron affintiy is
energy change when one e- is added to a neutral atom of element (Na + e-) = Na-
moving across, EA
increases
why does EA increases across period
increase in # of val e- , elements want to have full octet
going down, EA
decreases
why does EA decrease going down a group?`
e- further away from nucleus due to increasing atomic radii
which element has highest e- affintiy?
fluorine
put elements in order of increasing EA: Be, C, K, Ca
K<Ca<Be<C
Ionic Radii has
cation (+) anion (-)
is a cation bigger than its parent atom?
smaller bc e- removed making e- cloud smaller
is anion bigger than its parent atom?
bigger bc e- gained, increasing radius
which of following atoms or ions bigger? Ca or Ca^2+
Ca
S or S^- bigger?
S^-
Electronegativity is
ability of atom in chemical compound to attract e-
most electronegative compound
Flourine
moving across table, electrongeativty
increases
why does electroneg increase across table
charge on nucleus increases which attracts more e-
moving down table, electroneg
decreases
why does electroneg decrease going down table
bc size of atom increases , so e- cannot be pulled as close
put following elements in order of increasing electroneg: F, As, Sn, S
Sn<As<S<F
Octet Rule
atoms lose/gain/share e- to get to 8 val e-
if F wants to get 8 val e- how many e- does it need to gain?
1
if Mg wants to get 8 val e- how many e- does it need to lose?
2
smallest atomic radius=
noble gases
which group have largest atomic radii
metals
atomic radii cannot be measured directly bc electron cloud surrounding the nucleus does not have a clearly defined (charge, mass, outer edge, probability)
outer edge
atom becomes negatively charged when an electron is
gained
difference between electroneg + ea
ea gains e- electroneg ability to attract e- from other atom
Note
Flashcard