Download Agenda 11/4/2016

Agenda 11/4/2016
Slip Quiz
Trends in Properties in the Periodic table explaining the patterns (notes from slides)
IUPAC Announces New names for elements
Long form periodic table
Homework
Slip Quiz 1
1.
Which of the following has 8 valence
electrons? Explain how you decided.
antimony, aluminum, argon, arsenic.
2. Which 2 elements in the list would have
the same number of valence electrons?
How many? How do you know?
Correct your answers
1.
Which of the following has 8 valence
electrons? Explain how you decided.
antimony, aluminum, argon, arsenic.
Argon has 8 valence electrons - group 18
2
2
6
2
6
2
6
1s 2s 2p 3s 3p
[Ne]3s 3p
8 electrons in outermost energy level orbitals
antimony, aluminum, argon, arsenic.
Antimony and arsenic are in the same group
(Grp 15) in the Periodic table and all
elements in a group have same number of
valence electrons.
As electron config. [Ar]3d104s24p3
5 valence electrons
This 2D model is useful for thinking
about the size of atoms and how
they might change along periods and
down groups in the periodic table
e-e(showing electrons in
Energy levels, increasing
ee- e- 11+ eeeIn energy as the levels
ee- eIncrease in size).
Atomic radius vs. Atomic Number (take notes under graph)
Group trends in atomic radii
Atomic Radii (size of atoms) Main Group
Generally Atomic radius increases down a
group
Nuclear charge increases down a group
- electrons are added to successively higher
principal energy levels
- the orbitals are larger in size.
-
Generally Atomic radius increases down a
group
Nuclear charge increases down a group
- electrons are added to successively higher
principal energy levels
- the orbitals are larger in size.
- the increased distance offsets the greater pull of
the increased nuclear charge
-
Generally Atomic radius increases down a
group
Nuclear charge increases down a group
- electrons are added to successively higher
principal energy levels
- the orbitals are larger in size.
- the increased distance offsets the greater pull of
the increased nuclear charge
- Also the electrons in the inner orbitals shield the
outermost electrons from the pull of the nucleus
Atomic Radii trend across a period
Generally Atomic radius decreases across
a period
Nuclear charge increases across a period
- electrons are added to orbitals in the same principal
energy level
-
Generally Atomic radius decreases across
a period
Nuclear charge increases across a period
- electrons are added to orbitals in the same principal
energy level
- Moving across a period the increased nuclear
charge increases the pull of the nucleus on the
electrons in the orbitals in that energy level
-
Generally Atomic radius decreases across
a period
Nuclear charge increases across a period
- electrons are added to orbitals in the same principal
energy level
- Moving across a period the increased nuclear
charge increases the pull of the nucleus on the
electrons in the orbitals in that energy level
- the outermost electrons are pulled closer to the
nucleus and atomic radius gets smaller
Note on atomic radius - measuring it
- Electron cloud - based on probability - does not
have a clearly defined edge
- Atomic size defined by how closely an atom lies to
a neighboring atom - tends to vary in different
substances
- For metals - atomic radius is defined as half
distance between adjacent nuclei in a crystal of the
element
Atomic radius vs. ionic radius
An ion is an atom or bonded group of atoms
that has a positive or negative charge.
Atomic
radius
e- 11+ eeLarger
ee- eee- ethan
e-e-
Ionic
radius
Sodium atom
Sodium ion Na+
Electrically neutral
11+ - 10- = +1 charge
Periodic Variation in Chemical Properties
is defined as the
energy required to remove an electron from
a gaseous atom.
Ionization energy
First ionization energy is energy needed to remove
the first electron from a gaseous atom.
Periodic Variation in Chemical Properties
The higher (larger) the ionization energy value is, the
more energy is required to remove that electron
from its gaseous atom (in other words, the more
strongly the nucleus of the atom is attracting that
electron).
p 167
Generally ionization energy _______ down
a group
p 167
p 167
p 167
Generally ionization energy decreases
down a group
Nuclear charge increases down a group but:
- electrons are added to successively higher principal
energy levels
- the orbitals are larger in size.
- the increased distance and the shielding by inner
electrons offsets the greater attraction between the
nucleus and the outermost electrons
Therefore, it takes less energy to remove an electron
from the larger atoms in the group.
Generally ionization energy ____________
across a period
-
p 167
Generally ionization energy increases
across a period
Nuclear charge increases across a period, but:
- Therefore ...
Generally ionization energy increases
across a period
Nuclear charge increases across a period
- electrons are added to orbitals in the same principal
energy level
- Moving across a period the increased nuclear charge
increases the attraction between the nucleus and the
electrons in the orbitals in that energy level
Therefore it is more difficult (takes more energy) to
remove an electron from the atoms as we move across
the period.
Electronegativity is defined as the relative
ability of an atom to attract electrons towards
itself through a chemical bond.
Measured in units called Paulings.
(We leave out noble gases, they form too few
compounds to collect sufficient data.)
Variation in Electronegativity in Paulings
Group and Periodic Trends in
Electronegativity?
Generally electronegativity ____________
down a group
Generally electronegativity __________
across a period
Group and Periodic Trends in
Electronegativity?
Generally electronegativity decreases
down a group
Generally electronegativity increases
across a period
As we read the IUPAC announcement
Notice how scientists communicate with
each other.
Notice what is involved in naming new
elements currently.
115
Ds
Rg
Cn
Nh
Fl
Mc
116
Lv
117
118
Ts
Og
Long Form Periodic Table
Cut and
stick the
periodic
table you
have:
Long Form Periodic Table Use what we learned
Cut and
stick the
periodic
table you
have:
from creating the left
step periodic table to
make sure La and Ac
are in the f block and Lu
and Lr in the d block.
Long form Periodic table - shade or label the 4
blocks somehow - you decide where you want H and
He.
Fold to hide the transition elements Put a title on this format :
Main Group Elements (Representative elements)
Electrons in atoms Chapter 5
Notes packet to fill in some of the gaps
between what I’ve said and you’ve
researched or discovered using the
simulations and to re-kindle what you
learned about waves in physics earlier.
Homework
Ch 5. The Electrons - notes packet
Unit 3 The Periodic Table and Electrons
Study Guide for Content Mastery
Review graphing checklist also.
Test on Thursday, Nov 10th.