Atomic Structure Worksheet
1. Name the three particles of the atom and their respective charges
a._________________
______________________
b._________________
______________________
b._________________
______________________
2. The atomic number tells you the number of __________________________ in one atom of an
element. It also tells you the number of _____________________ in a neutral atom of that element.
The atomic number gives the “identity” of an element as well as its location on the Periodic Table.
No two different elements will have the _______________ atomic number.
3. The ___________________ of an element is the average mass of an element’s naturally occurring
atoms.
4. The ___________________ of an element is the total number of protons and neutrons in the
____________________ of the atom.
5. The mass number is used to calculate the number of _____________________ in one atom of an
element. In order to calculate the number of neutrons you must subtract the _________________
from the _____________________.
6. Give the symbol and number of protons in one atom of:
Lithium ________________________
Bromine __________________________
Iron ___________________________
Copper ___________________________
Oxygen ________________________
Mercury __________________________
Arsenic ________________________
Helium ___________________________
7. Give the symbol and number of electrons in a neutral atom of:
Uranium _______________________
Chlorine ___________________________
Boron _________________________
Iodine _____________________________
Antimony ______________________
Argon ______________________________
8. Name the element which has the following amount of particles.
26 electrons, 29 neutrons, 26 protons ______________________________________________
53 protons, 74 neutrons _________________________________________________________
2 electrons (neutral atom) _______________________________________________________
20 protons ___________________________________________________________________
0 neutrons ___________________________________________________________________
9.
10. a) The subatomic particle with no electrical charge is the __________________
b) The subatomic particle with a positive charge is the __________________
c) The subatomic particle with a negative charge is the __________________
d) There are the same number of these two particles in an atom: ___________________ and
___________________
e) The atomic number is the same as the number of ___________________
11. Where is most of the mass of an atom located? _____________________________________
12. Which particles account for the mass number of the atom? _______________ and _______________
13. Complete the following table
Symbol
Atomic
Number of
Number of
Number of
number
protons
neutrons
electrons
9
B
S
19
13
Mass