between you and a partner, grab one textbook…
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Turn to p. 193 (Organize Elements minilab) Cut a piece of construction paper into 10 squares and write the information for each element on each separate sheet Follow the instructions and answer the questions on a separate sheet (one sheet per pair). Between you and a partner, grab one textbook…. - PowerPoint PPT PresentationTRANSCRIPT
Turn to p. 193 (Organize Elements minilab)
Cut a piece of construction paper into 10 squares and write the information for each element on each separate sheet
Follow the instructions and answer the questions on a separate sheet (one sheet per pair)
Chapter 6
J.W. Dobereiner Early 1800’s, classify elements in sets of 3
This trend didn’t work for most of the elements known at the time
Element Mass
Li 7
Na 23
K 39
1865 – noticed trend that every 8th element had same properties (law of octaves)
Unfortunately, this didn’t work for all the known elements at the time, and it was dismissed
Considered the father of the modern Periodic table
arranged by increasing atomic mass (1869)
Discovered that the # of protons = atomic number
Developed concept of arranging PT by atomic number
Periodic law – there is a periodic repetition of properties when elements are arranged by atomic #
Periods vs. groups/families
Metals vs. nonmetals vs. metalloids What are some properties? Are all nonmetals gases?
Representative elements vs. transition metals vs. inner transition metals
What do all elements in the same group have in common?
Valence electrons
All elements in the same group exhibit similar characteristics
Sodium and Potassium are both highly reactive in water
So, what subatomic particle is responsible for determining properties of an element?
How many valence electrons?
Alkali metals:
1 valence electron, s block
Alkaline earth metals:
2 valence electrons, s block
Halogens:
7 valence electrons, s and p block
Noble gases:
8 valence, totally filled s and p block, except for which element?
Helium – his s block is filled with only 2
Transition metals: (Groups 3B – 12B)
2 s-block electrons, and various d block electrons
Called transition metals b/c electrons can move around the d block
Inner transition metals:
2 s-block electrons and various f block electrons
Representative elements: (Groups 1A – 8A)
any of the s or p-block elements
Which atom has more shielding? We’ll be coming back
to this idea of shielding often
SHIELDING
Half the distance between the nuclei of 2 like atoms
No definite edge of electron cloud
atomicradius
Down the Groups What is changing about
the atom as we go down? # of shells = energy level More shells = bigger
atom
Across the Periods Same period means same
# of shells What is changing as we
go across a period?Rb
K
Na
Li
Be C F
Who is larger? Mg or S? Br or K? C or Sn?
Who is smaller? Li or N? F or I?
Put the following elements in order of increasing atomic radius
Ca, Fe, Br, O, Ba
An ion is an atom with a charge (+ or -)
In a sodium atom, how many protons and electrons do we have? How many valence e-? 11 p+ and 11 e- 1 valence e-
Can we lose protons? No, that would change the element
An atom is most stable when it has a full outer shell How many valence electrons = full?
An atom will lose or gain electrons to achieve this – whichever is easiest
Sodium has 1 valence electron. Do you think he loses or gains? Loses, then there will be 1 more proton
than electrons
If an atom has 2 valence e-, what will it do?
What group is this? What charge?
What charge does aluminum form? Lose or gain? +3, loses 3 electrons
If an ion is positive it has ______ e-
If an ion is negative it has ______ e-
Na Na+
e-
F e-F-
Who is larger? Mg or Mg2+? S or S2-? O2- or F1-?
First, determine if you have lost or gained electrons… Which particle do you have more of (who has the power?)
IE is the energy required to remove an electron from an atom (and make it an ION)
KEEP SHIELDING IN MINDBabysitter analogy
A couple First Ionization Energies:Li = 520 kJ/molO = 1310 kJ/mol
Who is harder to take an electron from?
Which has the higher ionization energy? Li or N? Cs or Li? O or S?
Which has the lower ionization energy? K or Fe? F or Br?
Warm up:As we go down the groups on the PT, the
size of the atom __________, making it __________ to take an electron away, making the ionization energy __________
As we go left to right across a period, the size of the atom _________, making the ionization energy __________.
Arrange in decreasing ionization energies:
Cr, Br, I, Li, N
How well an element can attract electrons from another element in a bond Atoms fill their outer shells when they bond
with another atom How might EN relate to IE?
If it’s hard to take an electron away, what kind of attraction do you think it has?
What do you think the electronegativity of a noble gas might be? Do they want to bond? Zero
Arrange in order of increasing electronegativity:
Mg, F, Ne, Cs, Al
UP
& OVER
IE and EN increase
RaDius Decreases
But it is good to understand the WHY so you can double check yourself…
Put in order of decreasing atomic radius:
Ca, Al, Ne, Rb, Br, Au, Zn, C
What order is this for ionization energy? (increasing or decreasing)
Skip #8
Add this question (doesn’t matter where):Determine the larger radius in the following:
a. Mg or Mg2+ (what are the the
b. Cl or Cl1- things with charges
c. Cl1- or P3- called, and how do
they get those charges?)
Between you and a partner, grab a textbook: Turn to p. 193 (Organize Elements minilab) Cut a piece of construction paper into 10
squares and write the information for each element on each separate sheet
Follow the instructions and answer the questions on a separate sheet (one sheet per pair)
When finished, turn it in and grab a BINGO card