Name______

Chemistry: Atomic Structure Review Hr____ Date______

Particles of the Atom

ü  Proton, neutron, electron

ü  Charges, location, masses

ü  Mass Number, Atomic Number

History of the Atom

ü  John Dalton

o  Atomic Theory (know postulates)

o  What was right/wrong?

ü  JJ Thomson

o  Cathode ray tube

o  Plum-pudding model

ü  Rutherford

o  Gold Foil Experiment

o  Nucleus

ü  Bohr

o  Bohr Models

ü  Quantum Mechanical Model

o  Current theories

Isotopes

ü  Same element (protons), different masses (neutrons)

ü  Complete Atomic Designation

ü  Average Atomic Mass

ü  Radiactive Isotopes

·  Half-Life Decay

Electron Configuration

ü  Energy levels, orbitals, filling order

ü  Noble Gas Configuration

ü  Orbital Diagrams

ü  Valence electrons vs. Kernel (core) electrons

Periodic Table

ü  s-block, p-block, d-block, f-block

ü  charges (+1, +2,…..2-, 1-)

ü  Naming Ions

......

Review Questions for Atomic Structure Unit

(1) Using your vocabulary and your notes, fill in the following blanks.

Protons are POSITIVELY charged particles in the NUCLEUS of an atom. The protons have a mass of approximately ONE AMU. The number of protons in the nucleus, also called the ATOMIC NUMBER, is responsible for determining the type of atom, or the ELEMENT. The NEUTRONS are also in the nucleus with the protons, together their sum is the MASS NUMBER. Neutrons are almost equal in mass to the protons and are NEUTRAL in charge. NEUTERONS are responsible for creating isotopes. Outside the nucleus are the ELECTRONS which can be gained or lost to produce IONS. Positively charged ion are called CATIONS, while negatively charged ions are called ANIONS.

(2)  Using your vocabulary and your notes, complete the following table.

Scientist / Experiment/Observation / Discovery or Major Contribution / Drawing of their Model
Democritus
Dalton / ------
Law of conservation of mass,
Definite composition,
Multiple composition / Atomic Theory /
Thomson / Cathode ray tube / Electrons, protons
(plum-pudding model) /
Rutherford / Gold-Foil Experiment / Nucleus,
Atom is mostly empty space. /
Bohr / Electrons have only specific energy levels and distances from the nucleus that are allowed. / Electrons in ORBIT – fixed path
(planetary model) /
Math / probability
s-, p-, d-, f-orbitals / Quantum Mechanical Model /

(3) The element Chemistrium (Ch) has 2 varieties, Ch-110 and Ch-112. Ch-110 has a % abundance of 73%. Find the average atomic mass of Ch.

AAM = (% “A”)(mass “A”) + (% “B”)(mass “B”)

AAM = (0.73)(110 amu) + (0.27)(112 amu)

AAM = 80.3 amu + 30.24 amu

AAM = 110.54 amu

(4) The element Rubidium (Rb) has an average atomic mass of 85.468amu. Rubidium has two common isotopes, 85Rb and 87Rb. The average atomic mass of 85Rb is 85.00amu and the abundance of is 72.2%, what is the average atomic mass of 87Rb?

AAM = (% “A”)(mass “A”) + (% “B”)(mass “B”)

85.468 amu = (0.722)(85.00 amu) + (0.278)(x amu)

24.098 = 0.278 x

x = 86.68 amu = 87Rb

Complete the following table:

Atomic # / Protons / Neutrons / Electrons / Mass # / Net Charge / Complete Atomic Designation
23 / 23 / 28 / 18 / 51 / 5+ / 5+
83 / 83 / 126 / 80 / 209 / 3+ / 3+
72 / 72 / 106 / 68 / 178 / 4+ / 4+

(5) Why are some isotopes radioactive? Nucleus is unstable – wrong p/n ratio.

(6) What is a half-life? Time it takes for half of a radioactive element to decay

(7) Suppose the element, Chemistrium (Ch), has a half-life of 20y. How many grams of a 64g sample would be left after 4 half-lives pass? 5 half-lives pass?

4 g 2 g

(8) Consider the element, Governmentium (Gv), has a half-life of 50y. How many grams of a 128g sample would be left after 200y? 250y? 300y?

8 g 4 g 2 g

(9) Write the complete electron configurations for the following:

a) boron B = 1s22s22p1 B = [He]2s22p1

b) nitrogen N = 1s22s22p3 N = [He]2s22p3

c) cadmium Cd = 1s22s22p63s23p64s23d104p65s24d10 Cd = [Kr]5s24d10

d) manganese Mn = 1s22s22p63s23p64s23d5 Mn = [Ar]4s23d5

e) cesium Cs = 1s22s22p63s23p64s23d104p65s24d105p66s1 Cs = [Xe]6s1

(10) For each of the elements above, write the Shorthand Configuration off to the right.

(11) For each of the elements above, make an orbital diagram below. Make sure that all orbitals are correctly labeled.

Orbital diagram for Mn is shown below:

(12) Look at your periodic table. For each of the following elements, answer the following: How many valence electrons are there? Will this element steal or give away electrons and how many? What charge would this element have after following the octet rule? What is this element’s name as an ion?

Potassium
(K) / Magnesium (Mg) / Aluminum
(Al) / Phosphorus (P) / Sulfur
(S) / Bromine
(Br)
Total e- / 19 / 12 / 13 / 15 / 16 / 35
Valence e- / 1 / 2 / 3 / 5 / 6 / 7
Steal/Give Away
How many? / lose 1 / lose 2 / lose 3 / gain 3 / gain 2 / gain 1
Charge / 1+ / 2+ / 3+ / 3- / 2- / 1-
Name / potassium ion / magnesium ion / aluminum ion / phosphide ion / sulfide ion / bromide ion

(13) Why do elements want to be like Noble Gases? What do elements in the same column have in common (name at least 3)?

Noble gases have high stability (low energy) because they have a complete valence shell (octet).

Same number of valence electrons, same family name, all want to gain / lose same # of electrons forming ion(s) with the same electronic charge.