Download Unit 2 Review - RHSChemistry

Unit 2 Review
For a specific element the number of
______________
is the same but the number of
Protons
Neutrons
Electrons
________
and ___________
may vary.





Multiple forms of the same element with varying
Isotopes
numbers of neutrons are called ________________.
The same element with extra or not enough electrons
are called ________.
Ions
# of Neutrons
# of Protons
Mass number = _______________
+ _______________
What are the two ways to write an isotope of carbon with
7 neutrons?

Carbon-13
1. _______________
13
6C
2. _______________

Name the element which has:
Hydrogen
a. 1 proton _____________
Lithium
b. 4 n0, 3 p+, 3 e-________
Iron
c. 30 n0, 26 e-, 26 p+_____________
Argon
d. 18 e-, 22 n0, 18 p+_____________

What are valence electrons?
The electrons
in an atom’s outer most______
orbitals
_____
______________________

How many valence electrons in the
following atoms:
3
a. Al ________
2
c. Mg _________
5
b. P __________

How do the electron configurations for the
following elements end?
a. K _________
4s1
c.
b.
3
2p
N __________
6
4p
Kr _________
How are mass number and atomic mass different?
Mass number is the mass of the protons and
neutrons combined. Atomic mass is the
average mass of the element’s isotopes.

Describe Thomson’s experiments.
Used Cathode Ray Tube Experiment to
discover the first subatomic particle,
the electron. Proved electron was
negative by the reflection of the ray
due to the placement of a negative end
of the magnet

Describe Rutherford’s experiment.
Performed the Gold Foil Experiment
where he aimed positive alpha particles at
a thin sheet of gold foil. He observed
1) Most particles passed through, 2) Some
particles were slightly deflected and 3)
Some particles bounced back. These
observations proved the existence of a 1)
small, 2) positive, 3) dense nucleus.

Why are atoms neutral?
_____________________________
Equal numbers of negative electrons and positive protons

What is the charge of the nucleus of a Carbon
atom?
positive
_____________________________
Particle
Charge
Mass
Location
Electron
Negative
Approximately 0
Space surrounding
nucleus
Proton
Positive
1
Inside nucleus
Neutron
Neutral
1
Inside nucleus

Complete the table:
Include the mass number and atomic number in
names or symbols as discussed in class.
Element
Beryllium-9
Symbol
#p
4
#n
#e
5
4
21
23
Vanadium-44
23
Aluminum-28
13
15
13
1
1
1
Hydrogen-2
Mass # Atomic
Number
9
4
44
23
28
2
13
1

Complete the table:
Element
Electron
Configuration
Beryllium
1s2 2s2
Sn (No Orbital
Notation)
S
Orbital
Notation
Electron
Dot

Write the noble gas configuration for
krypton. Also, draw the electron dot
diagram.

Explain, in your own words ground state
for electrons.
Ground state electrons in the lowest possible energy
level are normal.

Explain, in your own words excited state
for electrons.
Excited state electrons take on energy and jump energy
levels.

Why did the chemicals used in the
“somewhere in the rainbow” lab give off
colors when heated?
The electrons absorbed the heat from the
burner, causing them to jump up to the
excited state. In order to return back to
“ground state” the electrons must give off
the extra energy – in the form of light.

Titanium has 5 naturally occurring isotopes.
Calculate the average atomic mass.
Mass (amu)
% Abundance
45.955
8.00
46.952
7.30
47.948
73.80
48.948
5.50
49.945
5.40

Sodium has two isotopes. Sodium-22 and Sodium23. Which is more abundant?
Sodium-23
________________
Accelerated Chem Only!

What do the following rules tell us about
electrons?

Aufbau Principle
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electrons fill orbitals from lowest to highest energy

Pauli Exclusion Princple

Max of 2 electrons per orbital & they must have
opposite spins

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Hund’s Rule
For orbitals of the same energy, 1 electron per orbital
and then double up