Transcript Notes Unit 3-3

Warm Up
9-28-15
1. What are valence electrons?
2. How many valence electrons do elements
in the alkali and halogen group have?
3. Which of these elements are metal?
Al, As, Cl, Li
4. What are the charges of the subatomic
particles?
Agenda
Homework
-Notes Unit 3-3
-Lab Conservation of mass
-WS Unit 3 Quiz Review
Quiz next class Unit 3
Finish review WS
SEAP - Science & Engineering
Apprenticeship Program
 Deadline to apply Oct. 23
 Must be 16 or older during the summer
 Spend 8 weeks during the summer doing
research at the Naval Surface Warfare
Center - (behind Norco College)
 $3,300 stipend for the 8 weeks
 https://seap.asee.org/
SEAP - Science & Engineering
Apprenticeship Program
 Applicant has to write 4 statements including:
 Career goals: describe your career goals and in which
way this program would help you fulfill those goals.
 Academic interests: describe any special interest you
may have that would make you a valuable participant.
Describe any awards or honors you have received.
 Research experience: describe any research
experience you may have in relation to this program.
 Technical skills: describe any technical skills you may
have, related to the science and engineering disciplines.
Unit 3-3
Periodic Trends
 Atomic radius
 Ionization energy
 Electronegativity
 Electron affinity
Periodic Trends
 Atomic Radius: The estimated distance
from the nucleus to the outer most
electrons
 Increases down a group
 As electrons energy levels are added,
the atom becomes larger
 Decreases across a period
 # protons increases which pulled the
v.e. closer to the nucleus
Atomic Radius Trend
Radius Increases
Radius decreases
Radius decreases
Periodic Trends
 Ionization Energy - The energy required to
remove one electron from an atom or ion
 Decreases down a group
 Electrons are farther from the nucleus and
easier to remove
 Increases across a period
Periodic Trends
 Electron Affinity - the energy change that
occurs when an electron is added to a
neutral atom
 Decreases down a group
 Increases across a period
Periodic Trends
 Electronegativity - the ability of an atom
to attract electrons to itself
 Decreases down a group
 Increases across a period
Check In
 Consider the following elements:
Ca,
Fe,
Ga,
Br
 Largest radius?
 Smallest radius?
 Highest electronegativity?
 Lowest ionization energy level?
Trends Summarize
Conservation of Mass
 Purpose: Find a method to test the law of
conservation of mass
 Materials:
electronic scale
125 mL flask
50ml graduated cylinder
1 balloon
5 g baking soda
15 mL vinegar
1) Weight of baking soda = _______g
2) Weight of compounds and reaction vessel
before reaction occurs = ________g
3) Weight of compounds and reaction vessel after
they reacted = _________g
Assignments
 Notes Summary
 Unit 3 Quiz review worksheet
due next class
(answers posted tonight after 7PM on my
website)