Slide 2 Catalyst 1.Open up the Bohrs Model educanon video for
todays class. Complete the questions associated with the video.
2.Put your laptop at 45 degrees and place your eyes on me so I know
when youre finished. End Slide 3 Slide 4 Review - Important Point
#1 The atom is mostly empty space. This is why most of the alpha
particles went through The majority of the atom does not have
anything in it. Slide 5 Review - Important Point #2 The atom has
very small, but very dense nucleus. Alpha particles that bounced
back were coming into contact with nucleus. Alpha particles were
deflected back because nucleus is positive. Slide 6 Review -
Nuclear Model Slide 7 Lecture 1.7 Bohr, Electronegativity, and
Atomic Radius Slide 8 Todays Learning Targets 1.6 I can explain the
development of atomic theory incorporating the contributions of
Dalton, Thomson, Rutherford, and Bohr. 1.7 I can define
electronegativity and explain how it relates to the charge of the
nucleus and the electron. Furthermore, I can explain how this trend
changes as you move throughout the Periodic Table. 1.8 I can define
atomic/ionic radius and explain how it relates to the charge of the
nucleus and the electron. Furthermore, I can explain how this trend
changes as you move throughout the Periodic Table. Slide 9 Niels
Bohr Refined Rutherfords model of the atom with his discovery in
1913. Slide 10 Slide 11 Slide 12 What Bohr Knew Shooting
electricity through the hydrogen excited electrons. Color produced
only for specific values Problem If electrons were free to roam,
then we should get all sorts of colors Slide 13 Slide 14 Bohrs
Solution Electrons are not free to roam in the electron cloud,
electrons are restricted to orbits or energy levels. Slide 15 The
Modern Model Rutherford s space and nucleus Dalton s atom Bohr s
energy levels Thompson s electrons Slide 16 SUMMARIZE Slide 17
Whats More Attractive? Slide 18 Magnets! How do they work? Slide 19
I. Nuclear Attraction The negatively charged electrons are
attracted towards the positively charged nucleus. The negatively
charged electrons are attracted towards the positively charged
nucleus. The more the electron feels the nucleus. The tighter it is
held The more the electron feels the nucleus. The tighter it is
held Slide 20 II. Electronegativity Electronegativity is the
measure of the ability of an atom to attract electrons. Slide 21
What do the arrows represent? How does the thickness of the arrows
relate to nuclear attraction? III. How does the size of the atom
relate to the positive and negative charges in an atom? Slide 22 a
As you move from the smallest atom to the largest atom, how does
the distance between the valence electrons and the nucleus change?
As you move from the smallest atom to the largest atom, how does
the attractive force between the valence electrons and the nucleus
change? What direction does this go on the periodic table? IV. Why
are the atoms getting bigger? Slide 23 Electronegativity Trends As
you go down a group, the electronegativity of an element decreases.
As you go across a period, the electronegativity of an element
increases. Slide 24 Slide 25 Slide 26 Why Electronegativity
Decreases Down a Group As you go down a group more orbits are
added. Electron Shielding Valence electrons become shielded from
the positively charged nucleus as you add more orbits. Electroneg.
decreases because there is a decreased ability of the nucleus to
attract electrons because of larger distance. Slide 27 Why
Electronegativity Increases Across a Period As you move across a
period you add more protons and electrons within the same orbit.
The larger amount of protons in the nucleus and electrons in orbit
show an increased attraction. This leads to increased
electronegativity as you move within a period. Slide 28 Class
Example Order the elements from smallest to largest
electronegativity: oxygen, beryllium, lithium, Slide 29 Table Talk
Order the elements from largest to smallest electronegativity:
chlorine, bromine, fluorine Slide 30 Stop and Jot Order the
elements from smallest to largest electronegativity: silicon,
aluminum, sulfur Slide 31 SUMMARIZE Slide 32 Master Chef - White
Board Races Slide 33 Slide 34 White Board Relay Race Problems
1.Which has a larger electronegativity: chlorine or silicon?
2.Which has a smaller electronegativity magnesium or calcium? 3.Put
the following elements in order from smallest electronegativity to
largest: B, F, N, O. 4.Put the following elements in order from
smallest electronegativity to largest: N, As, Bi, P. 5.Why does
bromine do a worse job of attracting electrons than fluorine? Slide
35 Atomic Radius Atomic Radius The distance from the center of the
nucleus to the outermost edge of the electron cloud Outer edge of
electron cloud Nucleus Slide 36 Atomic Radius Trends Atomic radius
increases as you go down a group on the Periodic Table. Atomic
radius decreases as you go across a period on the Periodic Table
Slide 37 Why Atomic Radius Increases Down a Group As you add more
electron shells to an element, the element becomes bulkier. This
means that as you go down a group, more orbits are added, so the
radius becomes bigger. Slide 38 Why Atomic Radius Decreases Across
a Period As you move across a period, more protons are added to the
nucleus. Also, more electrons are added within the same orbit. This
means there is a larger positive and negative charge, which results
in a higher attraction and a decrease in the radius. Slide 39 Slide
40 SUMMARIZE Slide 41 Master Chef - White Board Races Slide 42
Slide 43 Whiteboard Questions (T/F) 1.Atomic radius is the distance
from the center of the nucleus to the first electron orbit.
2.Atomic radius increases across a period and down a group.
3.Atomic radius decreases down a group because you are adding more
electron orbits. 4.Atomic radius decreases across a period because
there are less electrons in the same orbit. Slide 44 Whiteboard
Questions (cont) 5. Order the following from largest to smallest
atomic radius: Ca, Se, Ni 6. Order the following from largest to
smallest atomic radius: O, Po, S 7. Order the following from
smallest to largest atomic radius: Cs, F, Ga Slide 45 Exit Ticket
1. Define atomic radius 2. Define electronegativity. 3. Order from
largest to smallest electronegativity: Ca, Se, Ni 4. Order from
smallest to largest atomic radius: O, Po, S Slide 46 Rate Yourself
Based on the exit ticket and your current level of understanding,
rate yourself 1 4 on LT 1.6 - 1.8 Slide 47 Slide 48 Closing Time
Practice 1.7 Electronegativity and Atomic Radius UNIT 1 EXAM coming
up soon!
