Post on 17-Jan-2016
Question of the DayElements on the right side of the periodic table form _________ ions
Elements in the same group form ___________ ions
negative
The same
Day 2 1-27
Octet rule –
notes page 6
Octet rule – Atoms tend to gain, lose, or share electrons in order to acquire a full set of valence electrons (8)
What is electronegativity?
How does it
increase on
the p. t. ?
Electronegativity – ability to attract electrons in a bond
How does it increase on the p. t. ?
In this bond: Ba—S, which way do
elecs. Shift? WHY?
S, > electroneg.
Periodic TrendsIonization energy – energy needed to remove one electron from an atom
Li → Li+ + e-
… indication of how strongly an atom holds onto its outermost elecs.
Periodic TrendsThe graph on page 178 shows how ionization energies vary with atomic #
What element does the black point at (10, 2100) represent?
With respect to the periodic table ionization energies show 2 important trends…
Periodic TrendsWith respect to the periodic table ionization energies show 2 important trends…
1. Decrease as you move down a group
2. Increase as you move left to right across a period
Periodic Trends
How does the ionization energy trend compare to the atomic radius trend?
Does this make sense?
Periodic Trends
O
Be
Be
Cl
------
What’s bigger: ↑er I. E.:
O or C
Be or Ca
Na or Be
Cl of Al
Ca or B+3
IN NOTES
Periodic Trends
O
Mg
Be
Cl
------
What’s bigger: ↑er I. E.:
O or B
Mg or Sr
K or Be
Cl of Si
Sr or Al+3
IN NOTES
Periodic TrendsSuccessive Ionization energies (removing more than one electron from an atom):
- The 2nd > 1st, the 3rd > 2nd, the 4th > the 3rd
- but if you look at the I. E. s there is usually a large jump. Where? PAGE 178
Add the following trends:
Reactivity
Size (atomic radius)
Electronegativity
Assignments
Online assignment = shssci.wikispaces.com
Read section 6.3 and complete #s 18, 19, 21, 22, 24, 25 on page 182
BOTH DUE BY THE END OF THE PERIOD!!!
Periodic TrendsHow does atomic radius change?
Why?
How does ionization energy change?
Why?
Ionization energy
Fluorine
Noble gas
Inert
Group 17
Malleable
Ductile
Alkali metals
Francium
Period 4
Electronegativity
Octet Rule
Double periods
C
B
A
Atomic mass
*** _________ ***
_______
Similar properties:
_______________
__________________ (groups)
Families