CHAPTER 6.2
PERIODIC
TRENDS REGULAR
CHANGES IN
Almost as stable as fashion fads.
ATOMIC RADIUS
- Atomic
radius tells us about the _______ of
an atom
- Toradii,standardise
the measurement of atomic
the distance between the ________ of
-
two __________ _______ bonded together is
measured and divided by _______
Units for atomic radii are in _____________
PERIODIC + GROUP TRENDS
ATOMIC
RADII
-OFAtomic
radii generally
__________ from left to right
across a period
Increased number of protons and electrons, but
electrons are added to the same _________
__________ __________
Atomic radii generally __________ from top to bottom
within a group
Increased number of protons and electrons, but
electrons are added to new __________ _________
___________
-
IONS
- When
an atom gains or loses __________ and
becomes _________ and more _________
- This process is called ______________
- This
can happen during _____________ or in
a chemical ___________
IONISATION ENERGY
- Reactivity
of an atom depends on how easily
the atom is __________
- Ionisation
energy (IE) = the energy required to
_________ an electron (based on
-
____________ _________)
Measured in units of ________
For all atoms, the outermost electrons have
________ IE
-
PERIODIC TREND OF
IONISATION
ENERGY
Electron shielding:
outer electrons are
- shielded by the inner shell electrons
- As
more electrons are added, electron
shielding ___________
- Across
the periodic table from left to right, IE
___________
- Down
the periodic table from top to bottom, IE
___________
ELECTRON SHIELDING
PERIODIC TREND OF IONIC
RADII
Ionic radii of atoms are measured in ________
- __________, .˙. We need a ________
- Removing
electrons results in a _________
that is ________ than the parent atom
- Adding
an electron results in an _________
that is ________
ELECTRON AFFINITY
- Usually,
the formation of an _______ by adding an
electron __________ energy
- Electron
affinity (EA): energy change of a neutral atom
gaining an electron
- Electron
affinity is expressed as a _________
number in ______
- Across
the periodic table from left to right, EA
___________ (becomes more negative)
- Down
the periodic table from top to bottom, EA
___________ (becomes less negative)
ELECTRONEGATIVITY
- The
formation of chemical bonds always
involves the _________ electrons
- Atoms
of some elements have a greater
ability to _________ the valence electrons
-
involved in the bond (vs. Other elements)
Electronegativity: measure of the ability of an
atom to attract the ___________ when the
atom is part of a ___________
PERIODIC TREND OF
ELECTRONEGATIVITY
Electronegativity doesn’t have units but is a
- ___________ __________
- Fassigned
is the most electronegative atom and is
a value of 3.98 (usually just “4”)
- Across
the periodic table from left to right,
electronegativity ___________
- Down
the periodic table from top to bottom,
electronegativity ___________
ELECTRONEGATIVITY AND
IONIC
COMPOUNDS
When the difference between
- electronegativities of two elements is bigger
than ~1.7, there is a complete __________ of
electrons
This means that atoms with an
electronegativity difference > 1.7 will form
__________ _____________
-
ELECTRONEGATIVITY VIDEO
KNOW THE FOLLOWING
- How atomic and ionic radii are measured
- The
concepts/ definitions of atomic radii, ionisation energy, ionic radii,
electron affinity, and electronegativity
- The
periodic trends of atomic radii, ionisation energy, ionic radii,
electron affinity and electronegativity
- How electron shielding works
- How
electronegativity and ionic vs covalent bonding are related
(∆EN>1.7 = ionic)
HOMEWORK
-