SNC2D BOHR DIAGRAM WORKSHEET
NAME:
Use the information in your ‘Atomic Number, Mass Number Worksheet’ to help you draw complete Bohr Diagrams for the following twenty
elements. Some have been done for you.
electron
0N
1P
orbital shells
2P
2N
Element symbol
He
number of protons
number of neutrons
2P
2N
H
He
3P
4N
Li
Be
B
C
N
O
F
Ne
Mg
Al
Si
P
S
Cl
Ar
11P
12N
Na
19P
20N
K
Ca
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SNC2D – Chemistry: Chemical Reactions
Bohr Diagrams of the Atom
Atoms can be represented by Bohr diagrams. Bohr diagrams are useful for (i) better
understanding the properties of an element, and for (ii) predicting how an atom can combine
with others ____________________________.
In this model of the atom, the electrons travel around the nucleus in well-defined circular paths
known as ________________ or ___________ __________.
(a) Each electron in an atom ____________________________________.
(b) The farther away the electron is from the nucleus, ________________________.
(c) Electrons cannot exist between levels, _________________________________
_________________________________________________________________.
Steps for Drawing Bohr Diagrams (for use only with the first 20 elements):
1. Determine the number of electrons to be drawn:
# electrons = _______________________________
2. Draw a circle for the nucleus and write the ______________________ inside
3. Draw shells/levels around the nucleus. The ______________________ of the element in
the Periodic Table is the number of levels.
4. Fill the levels with electrons according to the following pattern:

1st level(nearest to the nucleus): filled first, with a maximum of ____ electrons;

2nd level: filled with a maximum of _____ electrons; _____________________
________________________________________________________________;

3rd level: filled with a maximum of _____ electrons,
Lewis Diagrams of Atoms
A Lewis diagram is a short-hand of a Bohr-Rutherford Diagram in which only the __________
______________ are written as _________.
Write the Lewis diagrams of the following elements, representative of the groups. Note that
every member of the group will have the _________ Lewis diagram.
Lithium
Beryllium
Boron
Carbon
Nitrogen
Oxygen
Fluorine
Neon
2
SNC2D – Chemistry: Chemical Reactions
Bohr Diagrams of the Atom
Atoms can be represented by Bohr diagrams. Bohr diagrams are useful for
(i) better understanding the properties of an element, and for (ii) predicting
how an atom can combine with others to form compounds.
In this model of the atom, the electrons travel around the nucleus in welldefined circular paths known as shells or energy levels.
(a) Each electron in an atom has a definite amount of energy.
(b) The farther away the electron is from the nucleus, the greater the energy
is.
(c) Electrons cannot exist between levels, but can only move up or down
from one level to another.
Steps for Drawing Bohr Diagrams (for use only with the first 20
elements):
1. Determine the number of electrons to be drawn:
# electrons = atomic number (for a neutral atom)
2. Draw a circle for the nucleus and write the element symbol inside
3. Draw levels (circles) around the nucleus. The period # (or row #)
of the element in the Periodic Table is the number of levels.
4. Fill the levels with electrons according to the following pattern:

1st level (nearest to the nucleus): filled first, with a maximum of 2
electrons;

2nd level: filled with a maximum of 8 electrons; draw electrons in pairs
for more than 4 electrons in this orbital;

3rd level: filled with a maximum of 8 electrons,
3
SNC2D – Chemistry: Chemical Reactions
Lewis Diagrams of Atoms
A Lewis diagram is a short-hand of a Bohr-Rutherford Diagram in
which only the valence electrons are written as dots.
Write the Lewis diagrams of the following elements,
representative of the groups. Note that every member of the
group will have the same Lewis diagram.
Lithium Beryllium
Nitrogen
Oxygen
Boron
Fluorine
Carbon
Neon
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