Atomic Worksheet
Name _______________________
1. Write the symbol or name for each of the following elements, as appropriate.
___________a. gold
___________e. Mn
___________i. lead
___________b. Hg
___________f. Zn
___________j. Co
___________c. uranium
___________g. fluorine
___________k. nitrogen
___________d. sodium
___________h. Fe
2. List the atomic number, the average mass number, and the mass number of the most
common isotope for each of the following elements.
Atomic
Most common isotope
Element
Average Mass
Number
mass number
Li
____________
____________
____________
N
____________
____________
____________
Al
____________
____________
____________
Ti
____________
____________
____________
Os
____________
____________
____________
3. Determine the number of protons, neutrons & electrons in each of the following isotopes:
Be – 10, As – 73, Kr – 85, and the most common isotopes of Mg, Al, La.
Isotope
Be – 10
As – 73
Kr – 85
Mg
Al
La
Protons
Neutrons
Electrons
4. Complete the table by filling in the empty boxes.
Element
Calcium (Ca)
Nickel (Ni)
Gold (Au)
Atomic
Number
79
6
Number of
Protons
20
28
Number of
Neutrons
20
Mass
Number
59
118
14
Isotope
Symbol
5. Assume that an element found in nature has two isotopes:
 40% is an isotope with mass number 35, and
 60% is an isotope with mass number 37.
What would be the average mass of the element?
6. Draw energy level diagrams for neutral atoms of C-14 and Ca-41.(see example of Si-30
below)
14 P
16 N
2 e-
4 e-
8e
Si-30
7. Indicate which element in each set is not in the same group or period as the others. (Hint:
“One of these things is not like the others, one of these things just doesn’t belong…”)
a. hydrogen, calcium, sodium, cesium
b. calcium, barium, magnesium, vanadium
c. sulfur, phosphorus, nitrogen, arsenic
d. uranium, neon, xenon, helium
e. Cl, Al, Tl, Na, Ar
8. Use the periodic table to decide which element in each of the following pairs is more
active.
a. potassium or sodium
b. oxygen or sulfur
c. chlorine or iodine
d. magnesium or calcium
9. Dmitri Mendeleev (1834 – 1907) was a Russian chemist that is credited with the modern
periodic table. He arranged the elements in order of increasing Average Atomic Mass,
not by Atomic Number. Mendeleev’s table as he derived it did not work for three pairs
of elements. He assumed their atomic masses were incorrect. Which pairs are reversed
in Mendeleev’s original table (don’t go past element 56)?