Transcript how big an atom is

Catalyst 12/1/11
1. How many valence electrons does Argon
have? Draw its Lewis dot structures.
2. Draw the Lewis dot structures for the
following elements: Ne, Br, Mn, Zn, Ca, K, Ti,
Xe, N
3. If an the atom of an element has a mass
number of 21 atomic mass units (amu) and
has 10 protons. How many neutrons does it
have? (Hint: # of neutrons = mass # atomic#)
4. The elements in group 3-12 are called the
_______ metals and are part of the ___ block.
5. What are the Group 17 elements called?
6. Which elements in the periodic table are
NOT REACTIVE or inert?
Agenda 12/1/11
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Catalyst
Announcements
Verbal Drill
Exploration of The Elements iPad App
Atomic Radius
Class Practice
Exit Slip
Homework
• Rough Draft of Data and Calculations
Section of Lab Report, DUE FRIDAY
12/2/11.
Class website:
http://mrgchem.weebly.com
Announcements
• Make up Unit#4 exam today at 7th
period or after school. A note will be
required if you need to take it after
Friday.
• Tutoring will be here in Room 22 for the
rest of this week.
Verbal Drill (2 minutes)
• One person speaking at a time (so everyone can
hear the question and answer!)
• You may only go once
• DO NOT CALL OUT IF ITS NOT YOUR TURN.
• If you don’t know the answer, have a classmate
help you. You still need to say the answer if its
your turn!
• Class with the most Verbal Drill points will receive
5 points in the Chapter 5 test
• P4: 15 pts P5: 13 pts P8: 14 pts P9: 16 pts
P10: 18 pts
The Elements iPad App
Objective
SWBAT define atomic radius and
describe the atomic radius trend in the
periodic table.
Quick Review
• Valence electrons are the electrons
found in the outermost electron shell*
and they are the electrons that
participate in chemical reactions.
(*You know how many valence
electrons by looking at the electron
shells with the highest principal quantum
number.)
Atomic Radius
Atomic radius is distance between the
nucleus and the valence electrons
measured in picometers.* (how big an
atom is)
(1 picometer = 1 x 10-12 meters)
*This depends on how it is measured.
Copy the words in bold.
Atomic Radius Periodic
Trends
• In general, atomic Radius increases
down a group (from up to down)
o This is because energy levels are added as
you go down the group.
• In general, atomic Radius decreases
across a period (from left to right)
Copy this. Yes, the whole slide.
Class Practice
1. As atomic number increases within
Group 15 on the Periodic Table, atomic
radius
• A) decreases, only
• B) increases, only
• C) decreases, then increases
• D) increases, then decreases
Class Practice
2. An atom of which element has the
largest atomic radius?
A) Fe
B) Mg
C) Si
D) Zn
3. Which list of elements from Group 2 on the
Periodic Table is arranged in order of increasing
atomic radius?
A) Be, Mg, Ca
B) Ca, Mg, Be
C) Ba, Ra, Sr
D) Sr, Ra, Ba
4.
5. Magnesium has an atomic radius of
160 pm and Aluminum has an atomic
radius of 143 pm. Which of the following
is the most likely value for the atomic
radius of Sulfur?
a. 150 pm
b. 190 pm
c. 130 pm
d. 205 pm
6. Beryllium has an atomic radius of 112
pm and Calcium has an atomic radius
of 197 pm. What is the most likely value
for the atomic radius of Barium?
a. 150 pm
b. 160 pm
c. 215 pm
d. 100 pm
7. Arrange the following elements in
order of DECREASING atomic radius: Ar,
Ne, He, Xe, Rn. (highest first then lowest)
Periodic Table Rap…
A little corny, but still entertaining. It
might help you remember the properties
in the periodic table.
Exit Slip
On a half a slip of paper, answer the
following:
1. Atomic radius increases:
2. Based on their locations on the
periodic table, which has a larger
atom: Calcium or Zinc?
3. Which has a greater atomic radius:
Potassium or Cesium?