Unit 2 Review

1
Unit 2 Review
2

• For a specific element the number of
  ______________ is the same but the number of
  ________ and ___________ may vary.
• Multiple forms of the same element with varying
  numbers of neutrons are called ________________.
• The same element with extra or not enough
  electrons are called ________.
• Mass number _______________ _______________
• What are the two ways to write an isotope of
  carbon with 7 neutrons?
• 1. _______________ 2. _______________

Protons
Neutrons
Electrons
Isotopes
Ions
Carbon-13
3

• Name the element which has
• a. 1 proton _____________
• b. 4 n0, 3 p, 3 e-________
• c. 30 n0, 26 e-, 26 p_____________
• d. 18 e-, 22 n0, 18 p_____________

Hydrogen
Lithium
Iron
Argon
4

• What are valence electrons? _____________________
  _______________
• How many valence electrons in the following
  atoms
• a. Al ________ b. P __________
• c. Mg _________

The electrons in an atoms outer most orbitals
3
5
2
5

• How do the electron configurations for the
  following elements end?
• a. K _________ b. N __________
• c. Kr _________
• How are mass number and atomic mass different?

2p3
4s1
4p6
Mass number is the mass of the protons and
neutrons combined. Atomic mass is the average
mass of the elements isotopes.
6

• Put the following people in order and then tell
  what they contributed to the understanding of the
  atom- Rutherford, Dalton, Aristotle, Thomson,
  Bohr, Democritus, Chadwick

Democritus came up with the first idea of an atom
Aristotle disagreed with Democritus
Dalton published his atomic theory (5
principles) in early 1800s almost all still
true today.
Thomson used Cathode Ray Tube Experiment to
discover the first subatomic particle, the
electron.
Rutherford used the Gold Foil Experiment to
prove the existence of a small, dense, positive
nucleus.
Bohr said electrons are in energy levels
Chadwick discovered the neutron (hard to find
b/c neutral in center.) Quantum Mechanics
current model of the atom.
7

• Explain the gold-foil experiment and the
  cathode-ray tube experiment. Remember Gold Foil
  Essay..

Review notes
8

• Why are atoms neutral?___________________________
  __
• What is the charge of the nucleus of a Carbon
  atom?_____________________________

Equal numbers of negative electrons and positive
protons
positive
Particle Charge Mass Location
Electron
Proton
Neutron
Space surrounding nucleus
Approximately 0
Negative
Positive
1
Inside nucleus
Neutral
1
Inside nucleus
9

• Complete the tableInclude the mass number and
  atomic number in names or symbols as discussed in
  class.

Element Symbol p n e Mass AtomicNumber
4 9
21 23
Aluminum-28
2 1
Be
Beryllium-9
5
4
4
23
Vanadium-44
44
23
V
13
15
13
Al
13
28
Hydrogen-2
H
1
1
1
10

• Complete the table

Element Electron Configuration Orbital Notation Electron Dot
Beryllium
Sn (No Orbital Notation)
S
1s2 2s2
11

• Write the noble gas configuration for krypton.
  Also, draw the electron dot diagram.
• What shapes are s and p orbitals?

S- Sphere
P- Dumbells
12

• Explain, in your own words ground state for
  electrons.
• Explain, in your own words excited state for
  electrons.

Ground state electrons in the lowest possible
energy level are normal.
Excited state electrons take on energy and jump
energy levels.
13

• 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.
Paris Hilton
The Hulk
vs.
14

• Consider the electrons found in Sulfur. How many
  total orbitals are found in sulfur? _______ Of
  all these orbitals, how many are found on the 2nd
  energy level? _________ Of the orbitals found
  on the second energy level, how many different
  orbital shapes are there? _________ How many
  electrons could fit into the entire 2p sublevel?
  ______ How many electrons could fit into one 2p
  orbital? ___________

9
4
2
6
2
15

• 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
  Sodium-23. Which is more abundant?
  ________________

Sodium-23