Download 1 - PTO

Structure
of the
Atom
2015
The identity of an element is determined
by the number of protons!!!
If you change the number of protons you
change the element!!!
Name: ____________________________ Class Period:_________
Re: SC 8/2015
!
Applicable!Next!Generation!Science!Standards:!
!
ATOMIC!STRUCTURE!AND!THE!PERIODIC!TABLE!
HSBPS1B1.!Use!the!periodic!table!as!a!model!to!predict!the!relative!properties!of!elements!based!on!the!patterns!of!
electrons!in!the!outermost!energy!level!of!atoms.!
Science!&!Engineering
Developing!and!Using!Models!Modeling!in!9–12!
builds!on!K–8!experiences!and!progresses!to!using,!
synthesizing,!and!developing!models!to!predict!and!
show!relationships!among!variables!between!
systems!and!their!components!in!the!natural!and!
designed!worlds.!!
•
Use!a!model!to!predict!the!relationships!
between!systems!or!between!
components!of!a!system.!(HSEPS1E1)!
DCI
PS1.A:!Structure!and!Properties!of!Matter!!
•
Each!atom!has!a!charged!substructure!
consisting!of!a!nucleus,!which!is!made!of!
protons!and!neutrons,!surrounded!by!
electrons.!(HSEPS1E1)!!!
CCC
Patterns!!
•
The!periodic!table!orders!elements!
horizontally!by!the!number!of!protons!in!the!
atom’s!nucleus!and!places!those!with!similar!
chemical!properties!in!columns.!The!repeating!
patterns!of!this!table!reflect!patterns!of!outer!
electron!states.!(HSEPS1E1),(HSEPS1E2)!
PS1.A:!Structure!and!Properties!of!Matter!!
•
•
Attraction!and!repulsion!between!electric!
charges!at!the!atomic!scale!explain!the!
structure,!properties,!and!transformations!of!
matter,!as!well!as!the!contact!forces!between!
material!objects.!(secondary!to!HSEPS1E!
1),(secondary!to!HSEPS1E3)!
Essential!Questions!&!Learning!Targets
HSBPS1B1 EQ1B1:!!Why!are!atoms!important?
A.
Be!able!to!evaluate!the!different!models!of!the!atom.!
B.!!!Be!able!to!analyze!the!structure!of!neutral!isotopes!and!ions.
HSBPS1B1 EQ1B2:!How!do!you!model!the!arrangement!of!electrons!in!an!atom?!
A.
Be!able!to!write!an!electron!configuration!for!neutral!atoms!and!ions.!
Different!patterns!may!be!observed!at!
each!of!the!scales!at!which!a!system!is!
studied!and!can!provide!evidence!for!
causality!in!explanations!of!
phenomena.!(HSEPS1E1),(HSEPS1E
2),(HSEPS1E3),(HSPS1E5)!
HS-PS1-1
Essential Question 1-1: Why are atoms important?
Learning Target A: Be able to evaluate the different models of the atom.
How do you study something that you cannot see?
Directions:
You will be visiting three stations. Answer the following questions for each station.
Think Tube:
Please do not attempt to open the tube. Begin to pull gently on the strings and explore what
happens.
List Observations:
Make a Claim: What does the inside of the tube look like? You may use drawings
and/or words.
Defend your claim with evidence: What observations led to your claim?
How confident are you in your claim? (circle)
not very confident
somewhat confident
very confident
Mystery Cubes:
Please do not attempt to look at the bottom of the cube. Using the visible sides of the cube,
decide what you think is on the bottom of the cube.
List Observations:
Make a Claim: What does the bottom of the tube look like? You may use drawings
and/or words.
Defend your claim with evidence: What observations led to your claim?
How confident are you in your claim? (circle)
not very confident
somewhat confident
very confident
Marble Boards:
Please do not attempt to look underneath the board. Roll a marble along the bottom board until
it hits the wooden shape. Draw the trajectory of the marble (on the top white board) from the
start of the roll until it finishes rebounding. Do this until you have enough data to make a claim
about the shape of the wooden block.
List Observations:
Make a Claim: What does the wooden shape look like? You may use drawings and/or
words.
Defend your claim with evidence: What observations led to your claim?
How confident are you in your claim? (circle)
not very confident
somewhat confident
very confident
HS-PS1-1
Essential Question 1-1: Why are atoms important?
Learning Target A: Be able to evaluate the different models of the atom.
The Atoms Family
Pre-Activity Questions:
1. What do you already know about atoms? List a few statements below.
2. What would a model of an atom look like? Draw one below and add any labels if necessary.
3. When do you think scientists first became aware of atoms? Give a time frame.
4. What would be some of the biggest challenges in studying atoms?
5. What is the value in having many scientists work on a theory?
Activity: The Atoms Family cards
Read each card in order and answer the questions that accompany each card. PLEASE DO NOT WRITE
ON THE ATOMS CARDS.
Card 1: Earliest Theories (400-600 BCE)
1. Why do you think that early Greek philosophers thought matter was made of only 4 basic elements?
2. Draw and label a model of an atom according to Democritus’ theory of the atom.
3. Why did Democritus choose the term “atoma” which meant “uncuttable” as the term to describe
atoms?
Card 2: Alchemy (500-1600)
1. What was the main goal of the alchemists?
2. What would the Alchemists’s model of the atom look like? Draw and label one below.
3. What positive contributions have Alchemists made?
4. What was beneficial about breaking away from studying alchemy towards the end of the 17th century?
Card 3: John Dalton (1766-1844)
1. Draw and label a model of what Dalton’s atom would look like.
2. Using Dalton’s symbols how would he have drawn a water molecule? Draw and label one below.
3. What could be some negatives to using Dalton’s symbols to represent different elements? Why do
you think Jons Berzelius system was adopted?
Card 4: J.J Thomson (1858-1940)
1. Summarize the new evidence that Thomson added to the model of atomic theory.
2. Draw and label a diagram of Thomson’s model of the atom.
3. Why is Thomson’s model of the atom referred to as the Plum Pudding Model?
4. What is the main difference between this new model and Dalton’s previous model of the atom?
5. What advances in technology made it possible for Thomson to successfully complete his investigation?
Card 5: Ernest Rutherford (1871-1937)
1. Explain the evidence Rutherford used to conclude that the atom had a positively charged nucleus.
2. Draw and label a model of what Rutherford’s atom would look like.
3. What was the main difference between Rutherford’s model of the atom and Thomson’s model?
Card 6: Niels Bohr (1885-1962)
1. Draw and label a model of what Bohr’s atom would look like. Include Chadwick’s discovery in your
diagram.
2. What is different about Bohr’s model of the atom compared to Rutherford’s model?
3. What happens when electrons change energy levels?
4. Explain the relationship between electrons and reactivity.
Card 7: Quantum Models (1920-present)
1. What new evidence did Quantum theory contribute to the model of the atom?
Post activity questions:
1. Describe a few ways the model of the atom has changed through time.
2. What is the value of including scientists whose models of the atom turned out to be incorrect?
3. Explain the role of conducting experiments and gathering evidence in creating models in science.
Notes:
Notes:
HS-PS1-1
Essential Question 1-1: Why are atoms important?
Learning Target B: Be able to analyze the structure of neutral isotopes and ions.
Inquiry Activity: Atomic Structure, Isotopes & Atomic Mass
Instructions: Study and use the information and diagrams provided to answer the
questions in this packet.
Part A: Structure of the Atom:
white oval = proton (+1 charge) mass= 1 amu
black oval = electron (-1 charge) mass= 0 amu
gray oval = neutron (0 charge) mass= 1 amu
•
•
These three particles that make up the atom are called sub-atomic particles.
The part of the atom where protons and neutrons are located is called the nucleus.
The following three diagrams represent three different isotopes of hydrogen atoms:
1
1
H
2
1
H
3
1
H
1. How many protons, neutrons, and electrons does each hydrogen atom have?
The following three diagrams represent three different isotopes of carbon atoms:
12
6
C
13
6
C
14
6
C
2. How many protons, neutrons, and electrons does each carbon atom have?
Notice the symbol notation used below each picture on the previous page…
In generic terms…
X = chemical symbol of element
Z = atomic number
A = mass number
A
Z
X
3. Where are the atomic numbers located on your periodic table?
4. Where are the mass numbers located on your periodic table?
Using your answers to questions 1 & 2…
5. In terms of subatomic particles, what information does the atomic number provide?
6. In terms of subatomic particles, what information does the mass number provide?
Part B: Isotopes
•
•
1
1
H, 2H, 3H are notations that represent isotopes of hydrogen atoms.
12
6
1
1
C, 13C, 14C are notations that represent isotopes of carbon atoms.
6
6
7. In terms of subatomic particles, what changes and what remains the same in
isotopes?
8. Using your answer to question #7, define the term isotope?
Critical Thinking Questions:
9. What single subatomic particle allows you to tell an atom of one element from an atom
of a different element?
10. In terms of subatomic particles, how does one isotope of hydrogen differ from
another isotope of hydrogen? How does one isotope of carbon differ from another
isotope of carbon?
Part C: Atomic Mass
The atomic mass unit (amu) is a special unit for measuring the mass of very small
particles such as atoms. Protons and neutrons have a mass of 1 amu, and electrons have a
mass of 0 amu.
20 protons
20 neutrons
13 protons
14 neutrons
40
20
Ca
periodic table atomic mass =
40.08 amu
27
13
Al
periodic table atomic mass =
26.982 amu
Critical Thinking Questions:
11. In atomic mass units (amu), what is the mass of an electron?
12. What is the mass of a proton and a neutron in atomic mass units (amu)?
13. Is most of the mass of an atom located in the nucleus or outside the nucleus? How
do you know?
14. Look at the calcium and aluminum examples above. Calcium (Ca-40) has a mass of 40
amu and aluminum (Al-27) has a mass of 27 amu. Based on the information in the picture,
how was this mass determined?
15. Given that hydrogen has three isotopes with the following masses; H-1, H-2,and
H-3.Take a look at hydrogen’s average mass on your periodic table. Based on this
information, which isotope would be the most common in nature? Defend your answer.
HS-PS1-1
Essential Question 1-1: Why are atoms important?
Learning Target B: Be able to analyze the structure of neutral isotopes and ions.
HS-PS1-1
Essential Question 1-1: Why are atoms important?
Learning Target B: Be able to analyze the structure of neutral isotopes and ions.
Isotopes
1. There are three known isotopes of the element hydrogen. List the number of protons,
electrons, and neutrons for each below.
Protium
1
1
H
Deuterium
2
1
H
Tritium
3
1
H
protons
electrons
neutrons
2. Explain why the atomic mass of hydrogen is 1.0079g and not a whole number.
3. Which of the hydrogen isotopes is most abundant in nature. Explain
4. Do the number of electrons in neutral isotopes of the same element differ? Explain.
5. Do the numbers of protons in neutral isotopes of the same element differ? Explain.
6. Do the numbers of neutrons in neutral isotopes of the same element differ? Explain.
7. Does the atomic number of an element change when the number of neutrons change?
Explain.
8. Does the mass number of an element change when the number of neutrons change?
Explain.
9.The element neon consists of three isotopes whose masses are 20.0 g, 21.0 g, and
22.0 g. The abundancies of these isotopes are respectively 90.92%, 0.25 %, and 8.83%.
Just by looking at the percents, what is the approximate molar mass of neon.
10.The element boron consists of two isotopes with masses of 10.0 g and 11.0 g. The
average molar mass of boron is 10.83 g/mol. Which isotope is more abundant? Explain.
Element Name
cobalt
Fluorine
Element
Symbol
U
C
Ba
Isotope Symbol
N-15
Th-230
K-40
Isotopes
Atomic Number
17
91
Mass
37
18
60
234
204
142
# Protons
30
8
5
82
# Electrons
# Neutrons
143
40
8
3
8
% Abundancy Problems
1. Determine the average molar mass of lithium if Li-6 represents 7.5% of lithium and Li7 makes up the other 92.5% (answer 6.925 amu)
2. A new element was discovered on the planet Xenopia. This element has two different
isotopes Z-9 and Z-11. Which isotope has the highest percent abundancy if the average
mass is 10.5 amu? Explain your answer.
3. Calculate the average atomic mass of magnesium if 79% of its atoms have a mass of
24 amu, 9.9% of its atoms have a mass of 25 amu, and 11.1% of its atoms have a mass of
26 amu. (answer 24.321 amu)
4. One of gallium’s isotopes weighs 69 amu and the other isotope weighs 71 amu. Explain
which isotope has the highest percent abundancy if the average mass is 69.8 amu.
5. Another new element was discovered on the planet Xenopia. The element (Xp) is
composed of an isotope weighing 34 amu and one weighing 37 amu. Explain which isotope
has the lowest percent abundancy if the average mass is 35.4 amu.
6. Sb-121 represents 57% of antimony. The other 43% is represented by Sb-123.
Determine the average molar mass of antimony. (answer 121.86 amu)
HS-PS1-1
Essential Question 1-1: Why are atoms important?
Learning Target B: Be able to analyze the structure of neutral isotopes and ions.
Inquiry Activity: Ions
Instructions: Study and use the information and diagrams provided to answer the
questions in this packet.
Ions: Ions are atoms of elements with charges, either positive or negative.
Atom
Ion
9 protons
10 neutrons
9 protons
10 neutrons
19
19 -1
F
F
9
9
Atom
12 protons
12 neutrons
Ion
12 protons
12 neutrons
24
12
Mg
24
12
Mg+2
16. Look at the fluorine atom and fluorine ion example above. How many protons,
neutrons, and electrons does each have?
17. Look at the magnesium atom and the magnesium ion example above. How many
protons, neutrons, and electrons does each have?
18. What is structurally different about an atom verses an ion? What is an ion?
19. How do you determine the charge on an ion?
20. Based on atomic structure, why is the charge on a neutral atom zero.
HS-PS1-1
Essential Question 1-1: Why are atoms important?
Learning Target B: Be able to analyze the structure of neutral isotopes and ions.
1.
Ions
Define an ion:
2.
List the number of protons , electrons, and neutrons for the following positive ion
and neutral atom.
40
20
Ca
40
20
Ca+2
protons
electrons
neutrons
A positive ion is called a:
3.
List the number of protons, electrons, and neutrons for the following negative ion
and neutral atom.
19
9
F
19
9
F-1
protons
electrons
neutrons
A negative ion is called an:
4. Do the numbers of protons for an ion differ from its neutral atom? Explain.
5. Do the numbers of neutrons for an ion differ from its neutral atom? Explain.
6. Do the numbers of electrons for an ion differ from its neutral atom? Explain.
7. Do the atomic numbers for an ion differ from its neutral atom? Explain.
8. Do the mass numbers for an ion differ from its neutral atom? Explain.
Element Name
H
Element
Symbol
Mg
Fe
hydrogen
oxygen
mercury
Ion Symbol
H+1
Ca+2
Al +3
Cl -1
S -2
Fe +2
# Protons
0
# Electrons
0
# Neutrons
Ions
Atomic Number
Isotope
Mass
1
35
16
12
45
14
30
78
27
10
10
10
36
23
46
1
29
11
35
47
1
40
108
16
35
23
201
56
Element Name
Calcium
Radon
Element
Symbol
Ni
Ba-137
N-14
Isotope
Symbol
26
29
11
Atomic
Number
59
64
23
224
35
24
Mass
# Electrons
10
9
18
7
8
9
10
23
28
10
54
13
# Protons
Atoms, Isotopes & Ions
Ion Symbol
Mg+2
Cl-1
P-3
Rn
Ni+2
# Neutrons
8
10
20
16
14
30
Notes:
Notes:
HS-PS1-1
Essential Question 1-2: How do you model the arrangement of electrons in an atom?
Learning Target B: Be able to write an electron configuration for neutral atoms and ions.
The Hotel Californium
Welcome to The Hotel Californium! You work at the front desk at the hotel and are
responsible for checking in guests. Although the customer is always right you do have strict
policies for assigning them to their rooms. Hotel management requires you to follow specific
rules when assigning guests to their rooms. The rules to follow are listed below.
The Hotel Californium offers a variety of room types. Some are very small with only one bed,
while others are more like suites that can hold a lot more guests. Here is a breakdown of the
types of rooms offered at Hotel Californium:
“s” rooms – 1 bed
“d” rooms- 5 beds
“p” rooms- 3 beds
“f” rooms- 7 beds
Each bed can hold one or two guests only. When placing guests into their rooms you must follow these
rules no matter how many people they come with.
Rule #1: From the Bottom Up (The Aufbau Principle)
Despite the fact that there is plenty of room at the Hotel Californium, rooms fill up in a very specific
order. Most of the customers come in pretty tired with their heads heavy and their sights dim, so it’s
important that they spend the least amount of energy possible to get to their room. This means that they
walk up the least amount of stairs and down the least amount of hallway possible. The hotel blueprint
page may offer some insight here.
Based on Rule #1, you should fill the rooms up in the following order (fill in the blanks):
1s, _____, 2p, 3s, _____, 4s, _____, _____, 5s, _____, 5p, 6s, _____, _____, 6p
Rule #2: Fill the Beds (Hund’s Rule)
You may have noticed the unorthodox room numbering system at The Hotel Californium. The manger
once heard voices down the corridor, which told him to number the rooms this way. He also is very
particular about how many beds are being used when guests are staying in the rooms. According to
management, guests must spread out and fill each bed in the room before they can double up in a bed.
One guest must be in every bed before a second guest can join them. Remember, extra guests are not
allowed to move up to a higher room until all of the lower rooms are filled.
How would you fit 4 guests into
the beds in the 3p room?
3p
How would you fit 8 guests into the
beds in the 4d room?
4d
Rule #3: No Funny Business (Pauli Exclusion Principle)
The manager wants to keep the Hotel Californium a family-oriented place, so he requires all guests to
sleep in opposite directions (head-to-toe) when sharing a bed. If Rule #2 is also in effect and there are
single people sleeping in adjacent beds then they all sleep in the same direction to watch the door. From
now on guests will be shown as arrows. This can be drawn as:
3s
3p
This sleeping in opposite directions is
also called having an opposite spin.
Use the hotel blueprint to answer the following questions.
1. (a) What is the maximum occupancy of the Hotel Californium? __________ guests
(b) How do you know this?
2. (a) How many guests does a “s” room accommodate if full? ________
(b) How many guests does a “p” room accommodate if full? _________
(c) How many guests does a “d” room accommodate if full? _________
(d) How many guests does a “f” room accommodate if full? __________
3. Using the arrow notations to represent guests, diagram what the hotel would look like with 34 guests.
You can diagram this on the first hotel blueprint. Make sure to follow all of the rules!
4. Using the arrow notations to represent guests, diagram what the hotel would look like with 45 guests.
You can diagram this on the second hotel blueprint. Make sure to follow all of the rules!
At the end of the night you have to let the landlord know which rooms are occupied. Of course he has a
very specific way for you to do this. He has you list the rooms in the same order by which they are
filled. To tell him how many people are in each set of rooms he requires you to use a superscript. Here
is an example of what he would expect for a night with 32 guests:
1s2 2s2 2p6 3s2 3p6 4s2 3d10 4p2
5. (a) What would you tell him for your diagram with 45 guests?
(b) What would you tell him if only 19 guests were staying there?
6. (a) Who really are the “guests” at the Hotel Californium?___________________________
(b) What do the different room types at the hotel represent?_________________________
(c) What do the different floors at the hotel represent? _____________________________
HS-PS1-1
Essential Question 1-2: How do you model the arrangement of electrons in an atom?
Learning Target B: Be able to write an electron configuration for neutral atoms and ions.
Electron Configurations
Draw and write the electron configurations for the following atoms or ions:
1. Ca
fourth
energy __
level
4s
third
energy __
level
3s
second
energy ___
level
2s
__ __ __
4p 4p 4p
2. N
__ __ __ __ __
3d 3d 3d 3d 3d
__ __ __
3p 3p 3p
fourth
energy __
level
4s
third
energy __
level
3s
__ __ __
2p 2p 2p
second
energy ___
level
2s
first
energy __
level
1s
__ __ __
4p 4p 4p
__ __ __ __ __
3d 3d 3d 3d 3d
__ __ __
3p 3p 3p
__ __ __
2p 2p 2p
first
energy __
level
1s
3. F
fourth
energy __
level
4s
third
energy __
level
3s
second
energy ___
level
2s
first
energy __
level
1s
__ __ __
4p 4p 4p
__ __ __
3p 3p 3p
__ __ __
2p 2p 2p
__ __ __ __ __
3d 3d 3d 3d 3d
4. S
fourth
energy __
level
4s
third
energy __
level
3s
second
energy ___
level
2s
first
energy __
level
1s
__ __ __
4p 4p 4p
__ __ __
3p 3p 3p
__ __ __
2p 2p 2p
__ __ __ __ __
3d 3d 3d 3d 3d
Draw and write the electron configurations for the following atoms or ions:
6. Al+3
5. Cu+2
__ __ __
__ __ __
fourth
4p 4p 4p __ __ __ __ __
fourth
4p 4p 4p __ __ __ __ __
energy __
3d 3d 3d 3d 3d
energy __
3d 3d 3d 3d 3d
level
4s
level
4s
__ __ __
__ __ __
third
3p 3p 3p
third
3p 3p 3p
energy __
energy __
level
3s
level
3s
__ __ __
__ __ __
second
2p 2p 2p
second
2p 2p 2p
energy ___
energy ___
level
2s
level
2s
first
energy __
level
1s
first
energy __
level
1s
7. Ar
8. He
fourth
energy __
level
4s
third
energy __
level
3s
second
energy ___
level
2s
first
energy __
level
1s
__ __ __
4p 4p 4p
__ __ __
3p 3p 3p
__ __ __
2p 2p 2p
__ __ __ __ __
3d 3d 3d 3d 3d
fourth
energy __
level
4s
third
energy __
level
3s
second
energy ___
level
2s
first
energy __
level
1s
__ __ __
4p 4p 4p
__ __ __
3p 3p 3p
__ __ __
2p 2p 2p
__ __ __ __ __
3d 3d 3d 3d 3d
Write the electron configurations for the following atoms or ions:
9. He
10. Li
11. Li+1
12. F
13. F-1
14. O
15. O-2
16. Na
17. Na+1
18. Al
19. Al+3
20. P
21. P-3
22. Kr
23. Rb
24. S-2
25. Cs+1
Write the neutral element that corresponds to each electron configuration:
26. 1s22s22p63s23p2
27. 1s22s22p63s23p64s23d104p65s24d7
28. 1s22s22p63s23p64s23d104p65s24d105p66s1
29. 1s22s22p63s23p64s23d104p65s24d105p1
30. 1s22s22p63s23p64s23d3
31. How do the parts of an electron configuration correspond to the periodic table?
32. State the regularity about the electron configurations of most ions?
33. Why do you think atoms form ions?
Explain what rule is being violated in the following electron configurations.
34. Fe
fourth
energy __
level
4s
third
energy __
level
3s
second
energy ___
level
2s
first
energy __
level
1s
__ __ __
4p 4p 4p
__ __ __
3p 3p 3p
__ __ __
2p 2p 2p
35. O
__ __ __ __ __
3d 3d 3d 3d 3d
fourth
energy __
level
4s
third
energy __
level
3s
second
energy ___
level
2s
first
energy __
level
1s
__ __ __
4p 4p 4p
__ __ __
3p 3p 3p
__ __ __
2p 2p 2p
__ __ __ __ __
3d 3d 3d 3d 3d
2. List what element each of the following would be by observing the number of electrons.
Study Guide
Structure of the Atom
Theories of the Atom
1. Be able to briefly describe early models of the atom (Alchemists, Democritus…)
2. For Thomson, Rutherford & Bohr, be able to describe how the structure of the
atom changed and explain how the experimental evidence collected supported that
change.
3. What subatomic particle did Chadwick discover?
4. Be able to describe/explain the applicable parts of the current model of the atom
(Quantum Theory) covered in class.
Structure of the Atom, Isotopes & Ions
5. Name each subatomic particle, their location in the atom, mass, and charge.
6. Be able to use the periodic table to determine the number of protons, electrons and
neutrons for any neutral isotope or ion.
7. Which subatomic particle determines the identity of an element?
8. What does the mass on the periodic table represent?
9. Define isotope.
10. Which subatomic particle(s) amount change and which stay the same in isotopes?
11. Define ion.
12. Which subatomic particle amount(s) change in ions?
13. What is a positive ion called?
14. What is a negative ion called?
Flame Tests and Light Spectrums
15. What causes different metal ions to produce different colors of light?
16. Give the corresponding flame color for the following metal ions:
a. K+1
b. Li+1
c. Sr+2
d. Ba+2
e. Cu+2
f. Na+1
g. Ca+2
Electron Configurations
17. What electron configuration do most ions form?
18. Describe how electron configurations related to the periodic table?
19. Why does the 4s orbital fill before the 3d orbital?
20. Which element in the 2p orbital is the first to double up in electrons? Explain your
answer.
Practice Problems
21. Determine the average atomic mass of Uranium if it has the following two isotopes; U-235
(0.720%) and U-238 (99.28%) (ans: 237.98amu)
22. Which isotope of neon is most abundant if the average atomic mass is 20.18 with
isotopes Ne-20, Ne-21 and Ne-22.
23. How many electrons are in a P -3 ion?
24. What is the charge on a lead ion with 78 electrons?
25. What is the atomic number of Si?
26. How many electrons does a neutral atom of Si have?
27. How many protons does a neutral atom of Cl have?
28. How many neutrons does S-34 have?
29. How many electrons does S-36 have?
30. How many electrons does S-2 have?
31. How many electrons does argon have in its 3p orbital?
32. How many electrons does sulfur have in its 3p orbital?
33. Complete the following table;
Element
a. Sn-120
mass
charge
+4
b. B-11
0
c. Ga-69
0
d. S-35
-2
e. Ra-228
+2
protons
neutrons
electrons
34. Which rules are violated in the following orbital diagrams
35. List the element represented by each of the following electron configurations.
a. 1s22s22p63s1
b. 1s22s22p63s23p64s23d6
c. 1s22s22p63s23p64s23d104p65s24d1
d. 1s22s22p63s23p64s23d104p65s24d105p4
36. Write the following electron configurations.
a. Ba
b. I
c. Sr +2
d. N -3
37. List the element represented by each of the following orbital diagrams.
Names and Symbols
Atomic #
1
Name
hydrogen
Symbol
H
2
helium
He
3
lithium
Li
4
beryllium
Be
5
boron
B
6
carbon
C
7
nitrogen
N
8
oxygen
O
9
fluorine
F
10
neon
Ne
11
sodium
Na
12
magnesium
Mg
13
aluminum
Al
14
silicon
Si
15
phosphorus
P
16
sulfur
S
17
chlorine
Cl
18
argon
Ar
19
potassium
K
20
calcium
Ca
26
iron
Fe
27
cobalt
Co
Atomic #
Name
Symbol
28
nickel
Ni
29
copper
Cu
30
zinc
Zn
35
bromine
Br
36
krypton
Kr
37
rubidium
Rb
38
strontium
Sr
47
silver
Ag
48
cadmium
Cd
50
tin
Sn
53
iodine
I
54
xenon
Xe
55
cesium
Cs
56
barium
Ba
78
platinum
Pt
79
gold
Au
80
mercury
Hg
82
lead
Pb
85
astatine
At
86
radon
Rn
87
francium
Fr
88
radium
Ra
92
uranium
U