CHAPTER 7 : PERIODIC
PROPERTIES OF THE
ELEMENTS
Periodic Properties
-Atomic Size
-Ion Size
-Ionization Energy
-Electron Affinity
-Electronegativity (Chap 8)
Atomic Size Trends
-increases top to
bottom(this is due to
increasing value of
principle quantum number,
n)
-decreases left to right
(this is due to increasing
effective nuclear charge)
Effective Nuclear Charge
(Zeff)- the net positive
charge experienced by the
outermost electron(s). Zeff
is less than Z due to
shielding (S).
Zeff = Z-S
Ion Size Trends
-Cations are ALWAYS
smaller than the metals
from which they were
formed
-Anions are ALWAYS
larger than the non-metals
from which they were
formed
WHY?
Ionization Energy-the
energy required to remove
an electron from a gaseous
atom, ion, or molecule
(Always ENDOTHERMIC).
Fig 7.11
I E Trends
-decreases from top to
bottom (this is due to
increasing size of the
atom)
-increases (generally) from
left to right (this is due to
increasing effective
nuclear charge)
mention irregularities
Use IE to explain shell
structure (values from
table 7.2)
Electron Configuration of
Ions are predicted by
adding electrons (nonmetals to give anions) or
removing electrons
(metals to give cations)
from the electron
configuration of the neutral
atom.
Isoelectronic - Species
which have the same
electron configuration.
Main Group Ions form to
achieve an electron
configuration isoelectronic
to the noble gases.
Transition Metals lose ns
electrons before (n-1)d
electrons
Be able to write electron
configuration for any
element or ion.
Electron Affinity - the
enthalpy change that
occurs when a neutral
atom or molecule gains an
electron in the gas phase.
(Very exothermic for
reactive non-metals such
as O, S, F, and Cl)
Metals
Nonmetals
Metalloids (Semimetals)
Location/Properties
(Figure 7.15 /Table 7.3)
metallic/nonmetallic
character
Give examples of the
following
metal + nonmetal=salt
acid + base = salt + water
metal oxide + water=
metal hydroxide(base)
metal oxide + acid= salt +
water
nonmetaloxide+water=acid
nonmetal oxide+ base=
salt and water
Rx of IA II A metals
Rx of VIA VIIA nonmetals