Atomic structure Test review Name:____________________
Date: ____________ Per:_______
HISTORY OF THE ATOM
Dalton is the Father of Modern Atomic Theory. His theory states: all matter is made of small, indivisible particles; these particles are different for each element; the particles are neutral, solid pieces of matter. He named the particles atoms.
Thomson discovered the electron using the cathode ray tube (CRT). He was surprised to find that the electrons from different elements were always the same. He determined that the electron has a negative charge. His model of the atom was a solid ball of positive charge with pieces of negative, electrons distributed throughout. The atom was neutral. (Called plum-pudding model.)
Rutherford discovered the nucleus using the gold-foil experiment and alpha particles.
His model was a small, solid nucleus with a positive charge surrounded by an empty area where electrons would orbit the nucleus. He said most of the atom was empty space and most of its mass was in the nucleus.
Bohr ’s model said the electrons orbit the nucleus in specific energy levels. (Called planetary model.)
Chadwick received credit for the discovery of the neutron.
AVERAGE ATOMIC MASS
Calculate the average atomic mass by multiplying the percent abundance by the mass number. Add up the answers.
Sample Problem: If 15% Fe-55 and 85% Fe56 what’s its average atomic mass? (.15 x
55) + (.85 x 56) = 55.85
AVERAGE ATOMIC MASS Practice Problems
Calculate the average atomic mass for the following.
1. 95% N-14, 3% N-15, 2% N-16
2. 98% C-12, 2% C-14

Atomic structure Test review Name:____________________
Date: ____________ Per:_______
PERIODIC TABLE
A. Mendeleev was the first to create a Periodic Table. It was arranged by atomic masses. He recognized that the chemical and physical properties of elements varied periodically.
B. Moseley updated the Periodic Table by arranging the elements according to their atomic numbers.
C. Vertical columns (going up and down) are called Groups. There are 18 groups.
Elements in the same group have similar chemical properties.
D. Horizontal rows (going left to right) are called Periods. There are 7 periods.
E. Some groups have family names: Group 1 are alkali metals, Group 2 are alkaline earth metals, Group 17 are halogens, and Group 18 are noble gases.
F. The size of an atom increases as it moves from top left to bottom right.
PERIODIC TABLE Practice Problems
Determine the period and group for the following elements.
1. S
7. Zn
2. Ag 3. Ca 4. Cl 5. W 6. Ni
8. Which element has properties different from the others? Cs, Ba, Li, K, Na

Atomic structure Test review Name:____________________
Date: ____________ Per:_______
ATOMIC STRUCTURE
B. Be able to determine an element’s atomic number, mass #, # of protons, # of electrons, and # of neutrons using the periodic table.
C. Know the properties of the subatomic particles; p + , n o and e -
Particle Location Charge Mass If the # changes
Proton Nucleus
Neutron Nucleus
Electron Electron cloud
1+
0
1-
1 AMU Have a new element
1 AMU
0 AMU
Have an isotope
Have an ion
D. Atoms are neutral. Ions have a positive or negative charge because the numbers of electrons and protons aren’t equal.
E. An ion’s charge = # of protons minus the number of electrons.
F. The atomic number = the number of protons.
G. Z = the nuclear charge or the number of protons
H. Cations are ions with a positive charge and anions have a negative charge.
I. The mass number = # protons plus # neutrons. It is also the average atomic mass rounded to the nearest whole number.
J. The molar mass i s the average atomic mass with the unit ‘grams’ added to it.
K. Isotopes have a different number of neutrons and therefore a different mass number.
ATOMIC STRUCTURE Practice Problems Complete the table.
Symbol AAM Mass
#
# protons # electrons
# neutrons
Cation, anion, isotope?
U-238
K 1+
S 2-
74
20
47
33
6
46
8

Atomic structure Test review Name:____________________
Date: ____________ Per:_______
E LECTROMAGNETIC SPECTRUM
A. Understand that electrons have energy levels and can move between them. When energy is absorbed by an electron the it moves up in energy. The electron releases a photon (radiation energy).
B. Energy of a photon can calculated using the equation E= h ᵧ where E is energy, ᵧ is frequency and h is Planck’s constant 6.63*10 -34 Js
C. Photons travel at the speed of light (C) 3.00*10 8 m/s the equation is C=λ ᶹ
D. The electromagnetic spectrum is a range of energy shown on the table below.
Practice Problems
1. Find the energy of a photon with a frequency of 3.20*10 17 hz
2. Find the wavelength of a photon with a frequency of 3.20*10 17 hz
3. What type of radiation would a photon with a wavelength of 6.20*10 7 m