atomic structure bff: homework helper and test prep guide for hs chemistry

for

High School Chemistry This topic is from my book:

Surviving Chemistry BFF: Homework Helper and Test Prep Guide.

Teachers and students can get it in Hard Copy or ebook from

SurvivingChem.com or Amazon.com

Copyright 2014. E3 Scholastic Publishing. SurvivingChem.com 5

7 22

23 34

35 52

53 70

71 86

87 102

103 118

119 132

133 152

153 170

171 192

193 212

213 220

221 231

233 236

Click here to get other topics from TpT


(cannonball) model

model

(nuclear) model

(planetary) model

(electron-cloud) model

The basic unit of matter.

John Dalton No internal structure.

J.J. Thomson Electrons and positive charges disperse throughout the atom.

Ernest Rutherford A small and dense positive (+) nucleus. Most of atom is empty space. Electrons revolve around the nucleus.

Neils Bohr Electrons in specific orbit . Orbits have fixed energy. Orbits are the electron shells.

Work of many Scientists over hundreds of years. The current model of the atom. Small, dense, positive nucleus. Protons and neutrons in the nucleus. Electrons in orbital outside the nucleus.

Probable location of finding an electron with a specific energy.

- + -- + - + - + - + - + - + - +

+

empty space

+

+

Earliest model

current model

e-

orbit (electron shells)

Orbital

36 Copyright 2014. E3 Scholastic Publishing. SurvivingChem.com

9. ErnestRutherford:

The Setup

Result 1

Conclusion 1

Result 2

Conclusion 2

8. J.J. Thomson:

Result 1

Conclusion 1

Result 2

Conclusion 2

A cathode ray tube containing two metal disks was connected to the + and ends of an electrical source. A positive (+) and negative (-) plates were placed above and below the cathode ray tube.

A beam of light (ray) travels from the cathode disk (-) to the anode disk (+).

The beam is composed of particles.

The beam was deflected toward the positive plate.

The particles in the beam are negatively charged (electrons).

were fired at a gold foil. A fluorescent screen detects paths of the alpha particles once they had hit the gold foil.

Most particles went straight through the gold foil undeflected.

An atom is mostly empty space (Empty Space Theory)

Very few particles were deflected straight back or at angles.

The center of an atom is dense, positive, and very small.


The inner core of an atom.

Dense, small, and positive.

Contains the protons and neutrons. Accounts for most of an atoms mass.

Protons (+ charge)

Electrons (- charge)

Neutrons (no charge)

+1 charge 1 atomic mass unit (1 amu) Located in the nucleus

0 charge 1 amu Located in the nucleus

-1 charge

0 mass ( 1/1836th of a protons mass)Located outside the nucleus in orbitals

Identifies each element. The same value as the number of protons.

The overall charge of the nucleus (+). The same value as the number of protons (or the atomic number).

Identifies isotopes of an element. The sum of protons plus neutrons.

Particles in the nucleus. Protons and neutrons.

Protons(+)

Neutrons

Electrons (-)

nucleus


Nuclide names

Nuclide symbols

Isotope notations

Nuclear diagrams

Atoms of the same element. Same number of protons (same atomic #) Different numbers of neutrons (different mass #s)

The average mass of an elements naturally occurring isotopes. Can be found on the Periodic Table or Can be calculated from mass numbers and percent abundances of an elements natural isotopes.

1 amu = 1/12th the mass of Carbon12

Energy levels of an atom.

Atomic model of an element that shows all the electron shells.Bohrs diagram for Sodium (Na) is shown on the right.

The arrangement of electrons in the electron shells of an atom.

22.898

Na

23

3rd shell

2nd shell 1st shell

2 e- 8 e-

1 e-

2 8 1 # of e-

1st 2nd 3rd shell

Mass Numbers (different)

Atomic Number (same). Number of Protons.

# of Neutrons (different) (Mass# - Atomic #)

11 p 11 p 12 n 13 n


Key Concept Definitions and facts Examples

2nd rd

3rd nd

(Bright-line Spectrum)

The lowest energy and most stable state of an atom. Electrons are in order from lowest to highest shell. Ground state electron configurations are given on the Periodic Table.

For sodium (Na): 2 8 1

The high energy and unstable state of an atom. Electrons are not in order. Excited state electron configuration of an atom is

different from what is given on the Periodic Table. For sodium (Na): 2 7 2 (may vary, but the

total e- must be 11)

An electron can move from one shell to another depending if energy is absorbed or released.

From low (ground) state to high (excited) state: The electron absorbs energy

From high (excited) state to low (ground) state: The electron releases energy

Band of colors produced when an excited electron releases energy as it returns from a high to low state.

The electron transition from 3rd shell nd shell will produce bright-line spectrum.

Shows line of colors produced at specific wavelengthsPattern of colors is unique for each element, and can be for identification.

A lab procedure in which compounds of metallic ions are heated to produce unique flame colors (light energy).

It can be used to make a rough identification of the metallic ion that is present in a sample.

H Li

Na

Unknown

The unknown sample contains H and Na.

I I I I I I wavelength (nm)


Key Concept Definition and facts Key examples

Sulfur 2 8 6

Na atom Na+ ion

S atom S2- ion

Electrons in the outermost level of an atom.

The last number in a configuration is always the number of valence electrons (for sulfur: 6). A neutral atom may lose or share its valence e-, or gain e- to fill up its valance shell during bonding.

Atoms with equal number of protons to electrons. A neutral S atom has: 16 protons (+)

16 electrons ()

Charged atoms with unequal numbers of protons to electrons.

Formed by a neutral (metal) atom losing e-. Na+ ion is formed when Na atom (a metal) loses 1 electron.

A +ion always has fewer e- than the atom. Na+ has 1 fewer electron than Na atom.

A +ion always has more protons than electrons. Na+ has more protons (11+) than electrons (10e-).

A +ion is always smaller than the atom. Na+ is smaller than Na atom.

Formed by a neutral (nonmetal) atom gaining e-. S2- ion is formed when S atom (a nonmetal) gains 2 electrons.

A ion always has more e- than the atom. S2- has 2 more electrons than S atom.

A ion always has fewer protons than electrons. S2- has fewer protons (16+) than electrons (18e-).

A ion is always larger than the atom. S2- is larger than S atom.

11+ protons 11+

11 e- electrons 10 e-

281 electron 28 configurations

16+ protons 16+

16 e- electrons 18 e-

286 electron 288 configurations

11+ 2 8 1 11+ 2 8

16+ 2 8 6 16+ 2 8 8


To find Key relationships Examples

(in neutral atoms)

(in ions)

= atomic # of the element = # of electrons (in a neutral atom) = = nucleon neutrons = mass # neutrons

= = protons = nuclear charge = mass # neutrons

= atomic # charge of the ion = = nuclear charge charge of the ion

= m= mass # atomic # = mass # electrons (in neutral atoms) = nucleons protons

= protons = electrons (in neutral atoms) = nuclear charge =

= neutrons + protons = (neutral atoms) = nuclear charge + neutrons = nucleons

= mass # = protons + neutrons = neutrons + electrons = nuclear charge + neutrons

= protons

= electron (in neutral atom) = mass # neutrons

An atom with a

+30 and 33 neutrons has 30 protons.

A neutral atom of has

35 electrons.

A charged atom with and has 42 electrons

An atom with a

has 125 neutrons.

An atom with a

and has an atomic # of 52. The atom istellurium.

An atom with and has a

mass # of 122 amu.

An atom with a

65 neutrons has a total of 113 nucleons.

An atom of argon with a mass of 40 amu has a nuclear charge of


protons = atomic number = nuclear charge = electrons = mass # - neutrons = nucleons - neutrons

mass # = nucleons = protons + neutrons = nuclear charge + neutrons = electrons + neutrons

neutrons = mass # - protons = nucleons protons

Atomic mass is the calculated average mass of all of an elements naturally occurring isotopes.

An example problem and solution (steps and setup) for calculating an atomic mass is given below.

A sample of an unknown element, X, contains the following isotopes: 80 % of 64X, 15% of 65X, and 5% of 66X. What is the average atomic mass of element X?

Step 1 Step 2 Step 3 Step 4

(% to decimal) x (mass #) = (product) (add all products)

80% of 64X .80 x 64 = 51.2 +

15% of 65X .15 x 65 = 9.75 = +

5% of 66X. .05 x 66 = 3.3

(.80)(64) + (.15)(65) + (.05)(66) =

64.25 amu

64.25 amu

atomic mass of X


1. Which conclusion was a direct result of the gold foil experiment?1) An atom is composed of at least three types of subatomic particles.2) An atom is mostly empty space with a dense, positively charged nucleus.3) An electron has a positive charge and is located inside the nucleus.4) An electron has properties of both waves and particles.

2. In the wave-mechanical model of the atom, orbitals are regions of the mostprobable locations of1) protons 2) positrons 3) neutrons 4) electrons

3. What is the charge and mass of an electron?1) Charge of +1 and a mass of 1 amu 3) Charge of +1 and a mass of 1/1836 amu 2) Charge of -1 and a mass of 1 amu 4) Charge of -1 and a mass of 1/1836 amu

4. Which phrase describes an atom?1) a positively charged electron cloud surrounding a positively charged nucleus2) a positively charged electron cloud surrounding a negatively charged nucleus3) a negatively charged electron cloud surrounding a positively charged nucleus4) a negatively charged electron cloud surrounding a negatively charged nucleus

5. Which total mass is the smallest?1) the mass of 2 electrons2) the mass of 2 neutrons3) the mass of 1 electron plus the mass of 1 proton4) the mass of 1 neutron plus the mass of 1 electron

6. Which statement concerning elements is true?1) Different elements must have different numbers of isotopes.2) Different elements must have different numbers of neutrons.3) All atoms of a given element must have the same mass number.4) All atoms of a given element must have the same atomic number.

7. Which value of an element is calculated using both the mass and the relativeabundance of each of the naturally occurring isotopes of this element?1) Atomic number 2) Atomic mass 3) Half-life 4) Molar volume

8. Which sequence represents a correct order of historical developments leading tothe modern model of the atom?1) Atom is a hard sphere atom is mostly empty space electrons exist in

orbitals outside the nucleus2) Atom is a hard sphere electrons exist in orbitals outside the nucleus

atom is mostly empty space3) Atom is mostly empty space atom is a hard sphere electrons exist in

orbitals outside the nucleus4) Atom is empty space electrons exist in orbitals outside the nucleus

atom is a hard sphere

9. An atom is electrically neutral because the1) number of protons equals the number of electrons2) number of protons equals the number of neutrons3) ratio of the number of neutrons to the number of electrons is 1:14) ratio of the number of neutrons to the number of protons is 2:1

Questions for Regents Practice Atomic StructureParts A and B-1 Multiple Choice


10. How do the energy and the most probable location of an electron in the thirdshell of an atom compare to the energy and the most probable location of an electron in the first shell of the same atom?

1) In the third shell, an electron has more energy and is closer to the nucleus.2) In the third shell, an electron has more energy and is farther from the nucleus.3) In the third shell, an electron has less energy and is closer to the nucleus.4) In the third shell, an electron has less energy and is farther from the nucleus.

11. During a flame test, ions of a specific metal are heated in the flame of a gasburner. A characteristic color of light is emitted by these ions in the flamewhen the electrons

1) gain energy as they return to lower energy levels2) gain energy as they move to higher energy levels3) emit energy as they return to lower energy levels4) emit energy as they move to higher energy levels

12. A particle of an atom contains 26 protons, 23 electrons, and 56 neutrons.What will be the correct atomic number for this particle?1) 26 2) 23 3) 56 4) 33

13. An atom with 21 neutrons and 40 nucleons has1) A nuclear charge of +19 3) A mass number of 612) A nuclear charge of +40 4) A mass number of 19

14. Which element could have a mass number of 86 atomic mass units and 49neutrons in its nucleus?1) In 2) Rb 3) Rn 4) Au

15. Which correctly represents two isotopes of element X?

1) 226 X and 226 X 3) 227 X and 227 X 91 91 91 90

2) 226 X and 227 X 4) 226 X and 227 X 91 91 90 91

16. Which atom is an isotope of oxygen?

1) 14 N 2) 16 N 3) 14 O 4) 17O7 8 7 8

17. What is the total number of nucleons in the nuclide 65 Zn?30

1) 65 2) 30 3) 35 4) 95

18. In which pair of atoms do the nuclei contain the same number of neutrons?1) Calcium-40 and Calcium-42 3) Bromine-83 and Krypton-832) Chlorine-35 and Sulfur-34 4) Iodine-127 and Bromine-80

Questions for Regents Practice: Atomic StructureParts A and B-1 Multiple Choice


19. Which is a ground state electron configuration of an atom in the fourth periodof the periodic table1) 2 8 4 3) 2 8 18 18 42) 2 8 18 4 4) 2 4

20. The total number of electrons found in the electron configuration of a neutralchromium atom is1) 24 2) 6 3) 13 4) 52

21. The highest amount of energy will be emitted by an electron when it moves fromthe1) 4th to 1st electron shell 3) 1st to 5th electron shell2) 1st to 4th electron shell 4) 5th to 4th electron shell

22. What is the total number of electrons in a Cr3+ ion?1) 3 2) 21 3) 24 4) 27

23. Which symbol represents a particle with a total of 10 electrons?1) N 2) Al 3) N3+ 4) Al 3+

24. Which electron configuration represents an atom of aluminum in an excitedstate?1) 2-7-4 2) 2-8-3 3) 2-7-7 4) 2-8-6

25. Element X has two isotopes. If 72.0% of the element has an isotopic mass of84.9 amu, and 28.0% of the element has an isotopic mass of 87.0 amu, theaverage atomic mass of element X is numerically equal to

(72.0 x 84.9) (28.0 x 87.0) 1) (72.0 + 84.9) x (28.0 + 87.0) 3) ------------------ + ------------------

100 100

(72.0 x 84.9) (28.0 x 87.0) 2) (72.0 - 84.9) x (28.0 + 87.0) 4) ----------------- - ------------------

100 100

26. The diagram below represents the nucleus of an atom

What are the atomic number and mass number of this atom?

1) The atomic number is 9 and the mass number is 19.2) The atomic number is 9 and the mass number is 20.3) The atomic number is 11 and the mass number is 19.4) The atomic number is 11 and the mass number is 20.

Questions for Regents Practice: Atomic StructureParts A and B-1 Multiple Choice


27. Based on the atomic mass and the natural abundances shown in the data tableshow a correct numerical set-up for calculating the average atomic mass of neon.

28. Based on natural abundances, the average atomic mass of neon is closest towhich whole number?

29. In terms of atomic particles, state one difference between these three isotopesof neon.

30. Explain, in terms of excited state, energy transitions, and ground state, how abright-line spectrum is produced.

31. Identify the two elements in the unknown spectrum.

32. Write an appropriate number of electrons in each shell to represent an Mg-26atom in an excited state. Your answer may include additional shells.

33. What is the total number of valence electrons in an atom of Mg-26 in theground state?

Questions for Regents Practice: Atomic StructureParts B-2 and C Constructed Response


Principal Energy Level (n)

Sublevel of an Electron

Orbital (Probable Location)

Spin Direction of an Electron

Uses a set of four quantum numbers to describe location and behavior of an electron in atoms.

1,2,3.. or K, L, M.. are used to designate the major energy level of an electron. An electron with a first quantum level number of 2 or L is in the second energy

s, p, d, f... are used to indicate the sublevel of an electron within a principal energy level.

The difference between the sublevels is the shape of their orbitals. s sublevel is always the first in any principal energy level. s sublevels have spherical shape. p sublevel is always next in any level. p sublevels have dumbbell-like shape

Shapes of d, f, g and h sublevels are too complex, and will not be discussed here.

x, y and z are used too describe the orbital (probable location) of an electron within a sublevel.

2px, 2py, and 2pz describe the three p orbitals of the second energy level.

s sublevels (regardless of the energy level) have 1 orbital. p sublevels have 3 orbitals.

d sublevels have 5 orbitals.

Each orbital, regardless of the sublevel, can hold a maximum of two electrons.

In full orbitals, the two electrons must spin in opposite directions to overcome

like-charge repulsion.

number of electrons

sublevel principal energy level


Ground state atoms have configurations that show completely filled lowest available sublevels

lowest energy increasing energy------------>

Shows arrangement of electrons in the energy levels and sublevels.

Shows distribution of electrons in the orbitals.

When placing electrons in orbitals: No more than two electrons in an orbital Each orbital in p, d, f..etc must have an

electron before pairing Two electrons in an orbital must show opposite spins ( Valence electrons are only the electrons in the s and p sublevels of the highest level.

Ground State for Na

Excited State for Na

H

He 2 e- 1s2

N

7 e-

S

1s2 2s2 2p3

16 e- 1s2 2s2 2p6 3s2 3p4

1 e- 1s1

Ground state orbital notations and electron configurations for four atoms are shown below.

all lowest sublevels have their maximum # of electrons.

the 2p sublevel is incomplete while 3s has an extra electron


PrincipalEnergy

Level (n)

Numberof

Sublevels

AvailableSublevels

Number ofOrbitals Available

Maximum number ofelectrons in energy level

(2n2) 1 1 1s 1 2

2 2 2s 2p

1 3 8

3 3 3s 3p3d

1 3 5

18

4 4

4s 4p4d4f

1 3 5 7

32

Note: Each orbital can hold a maximum of 2 electrons

34. What is the total number of occupied energy levels in an atom of neon in theground state?1) 1 2) 2 3) 8 4) 18

35. Which of the following sublevels has the highest energy?1) 2p 2) 3p 3) 3d 4) 4s

36. What is the maximum number of electrons that can be found in a 3s orbital of apotassium atom?1) 1 2) 2 3) 8 4) 18

37. Which is the correct electron configuration of a magnesium atom in the groundstate?1) 1s2 2s2 2p6 3s1 3p1 3) 1s2 2s2 2p6 3s22) 1s2 2s2 2p6 4) 1s2 2s2 2p6 3s2 3p1

38. An atom in the excited state can have an electron configuration of1)1s2 2p1 2) 1s2 2s2 3) 1s2 2s2 2p5 4) 1s2 2s2 2p6

39. What is the electron configuration of an Mn atom in the excited state?1) 1s2 2s2 2p6 3s2 3) 1s2 2s2 2p6 3s2 3p6 3d54s2 2) 1s2 2s2 2p6 3s2 3p6 3d6 4s1 4) 1s2 2s2 2p6 3s2 3p6 3d5

40. Which atom in the ground state has only three electrons in the 3p sublevel?1) Phosphorus 2) Potassium 3) Argon 4) Aluminum

41. Which atom in the ground state has two half-filled orbitals?1) P 2) O 3) Li 4) Si

42. What is the total number of completely filled principal energy levels in an atomwith a configuration of 1s2 2s2 2p6 3s2 3p6 3d10 4s2 4p1 ?1) 1 2) 2 3) 3 4) 4

43. Using quantum method ( s, p, d..), write electron configurations and draw orbitalnotations for the following atoms and ions.atoms: C, Al, S, Ar, Ca, Se ions: Li+, Mg2+, K+, F-, S2-, As3-


/;

Energy of an electron is quantized, meaning, it is specific for each energy level. The equation below can be used to calculate the energy, En , of an electron in a hydrogen atom if its principal energy level, n, is known.

Light is a form of electromagnetic radiation that travels at a of 3.00 x 108 m/sec.

Every electromagnetic radiation (different light colors) is emitted at a specific ( ). Frequency ( ) of light, in Hertz, indicates the

number of completed wave per second.

When an atom absorb or release energy in the form of electromagnetic radiation during electron transition from one energy level to another, the energy change,

(in Joules), can be calculated using this equation.

-2.178 x 10-18

En = ------------------ Joules n2

c = -----

= h = ----

= Plancks constant, 6.63 x 10-34 Joules.sec. = frequency of the radiation (1/sec or Hz) = wavelength of the radiation (m) = speed of light, 3.00 x 108 m/sec

44. Calculate the energy of an electron of a hydrogen atom in these three shells.a) n = 1 b) n= 2 c) n = 3

45. Violet light has a wavelength of 4.10 x 10-12 m. What is its frequency?

46. A helium laser emits light with a wavelength of 633 nm. What is the frequency ofthe light?

47. Calculate the wavelength of radiation with a frequency of 8.0 x 1014 Hz.

48. Green light has a frequency of 6.01 x 1014 Hz. What is the wavelength?

49. Calculate the energy of a photon of radiation with a frequency of 8.5 x 1014 Hz.

50. Calculate the energy of a gamma ray photon whose frequency is 5.02 x 1020 Hz.

51. Calculate the energy of a photon of radiation with a wavelength of 6.4 x 10-7 m.

52. What is the energy of light whose wavelength is 4.06 x 10-11 m?

53. An FM radio station broadcasts at a frequency of 107.9 MHz. What is thewavelength of the radio signal?


1. 2

2. 4

3. 4

4. 3

5. 1

6. 4

7. 1

8. 1

9. 1

10. 2

11. 3

12. 1

13. 1

14. 2

15. 2

16. 4

17. 1

18. 2

19. 2

20. 1

21. 1

22. 2

23. 4

24. 1

25. 3

26. 2

27. (.909 x 20) + (.003 x 21) + (.088 x 22) setup may vary

28. 20 29. They contain different number of neutrons. 30. Spectrum is produced when excited e- returned to ground state. (answer may vary) 31. He and H 32 2 8 1 1 or 2 7 3 (configuration may vary, BUT must have 12 electrons) 33. 2

Questions for Regents Practice Atomic Structure

Answers Topic 3

34) 2

35) 3

36) 2

37) 3

38) 1

39) 2

40) 1

41) 2

42) 3

44) n = 1 : -2.178 x 10-18 J

n = 2 : -5.45 x 10-19 J

n = 3: -2.42 x 10-19 J

45) 7.32 x 1019 Hz

46) 4.73 x 1014 Hz

47) 3.75 x 10-7 meters

48) 4.99 x 10-7 meters

49) 5.64 x 10-19 Joules

50) 3.33 x 10-13 Joules

51) 3.10 x 10-19 Joules

52) 4.89 x 10-15 Joules

53) 2.78 meters

43) Atoms

C: 1s22s22p4

Al: 1s22s22p63s23p1

S : 1s22s22p63s23p4

Ar: 1s22s22p63s23p6

Ca: 1s22s22p63s23p64s2

Se: 1s22s22p63s23p63d104S24p4 Ions

Li+ : 1s2

Mg2+ : 1s22s22p6

K + : 1s22s22p63s23p6

F- : 1s22s22p6

S2- : 1s22s22p63s23p6

As3- : 1s22s22p63s23p63d104s24p6

Additional Materials Answers to Questions

WHICH OF OUR BOOKS IS RIGHT FOR YOUR STUDENTS?

Let them choose from our

eBook School-license Deals

Surviving Chemistry BooksStudent and teacher friendly supplemental instructional books and exam preps

for high school chemistry and biology

As low as

$1

Online based; no downloading and no software to install.

Quick a nd easy access for all of your students anytime, anywhere.

Compatible with all brands of computers and browsers.

Mobile eBook format for on-the-go access with iPad, tablet or phone.

Visually stunning digital flipbook for students.

Easy to browse, read, search and print pages.

No screen advertisements to annoy and distract students.

Customized specifically for your school.

Our eBook Platform

per book

Take an additional 10 - 40% off

on SurvivingChem.com

Easy to Order Visit SurvivingChem.com

Choose a School-License Deal Select title(s) from our 7 books

Apply a discount code if applicable

Pay securely

For Instant Preview

ME BFF Rev2AS BFF Rev2AS D.pdfME BFF Rev2AS BFF Rev2

atomic structure bff: homework helper and test prep guide for hs chemistry

Documents