Objective 3 Worksheet
Bohr Models
Name
Period
In 1943, Niels Bohr described the atom as a planetary system with electrons orbiting around the nucleus. Bohr’s
model is incomplete, but it nonetheless is helpful in understanding why some atoms are very reactive and others
are less so.
Directions: complete each of the following models using what you know about atoms. The first is completed for
you as an example.
Atomic # 7__
Atomic Mass 14__
Atomic # ____
Atomic Mass_12_
Atomic # ____
Atomic Mass_40_
Element:_____________
Symbol C_
Valence e#____
Element:_____________
Symbol_____
Valence e#____
Atomic # ____
Atomic Mass_40_
Atomic # ____
Atomic Mass_11_
Atomic # ____
Atomic Mass_27_
Atomic # ____
Atomic Mass_32_
Element:_____________
Symbol_____
Valence e#____
Element:_____________
Symbol _B_
Valence e#____
Element:_____________
Symbol_____
Valence e#____
Element:_____________
Symbol_____
Valence e#____
Atomic # ____
Atomic Mass_37_
Atomic # ____
Atomic Mass_23_
Atomic # _10_
Atomic Mass_20_
Atomic # ____
Atomic Mass____
Element: Sodium
Symbol_____
Valence e#____
Element:_____________
Symbol_____
Valence e#____
Element:_____________
Symbol_____
Valence e#____
Isotope Name: Nitrogen
Symbol_ N_
Valence e#____
Element:_____________
Symbol_____
Valence e#____
Atomic # ____
Atomic Mass____
Element:_____________
Symbol _H_
Valence e#____
Atomic Structure and Valence Electron Practice
The purpose of this assignment is to help you become more familiar with the atomic
structure of some common elements by completing the chart below. For each element you have
been given enough information to fill all of the blanks.
Isotopic Name Element Atomic #
Symbol
2
Mass #
# Protons
Br
12
65
80
Aluminum-27
35
13
U
14
146
11
48
Ag
92
12
Krypton-84
Ca
#
electrons
4
12
30
#
neutrons
40
20
47
61
36
# Valence
elec.