Name: _____________________
Unit 2:6
Isotopes and Making Atoms
Period: _____________________
An isotope is a variation of an element. It has the same number of protons
(same element), but a different number of neutrons (different isotope).
Isotopes
Protons
Isotopes of Hydrogen
Because they each have
1 proton, they are all
hydrogen atoms, but are
different isotopes
because they have
numbers of neutrons .
Hydrogen 1
1p + 0n = 1
Isotopes of Beryllium
Neutrons
Hydrogen 2
1p + 1n = 2
Hydrogen 3
1p + 2n = 3
Reading the Tiles
The atomic mass
is an average.
Round it to
find the most
common isotope.
4p
4n
4p
5n
Beryllium 8
4p + 4n = 8
Beryllium 9
4p + 5n = 9
Finding the # of Neutrons
Atomic number
(number of protons)
Atomic mass
(average of all the isotopes)
Mass numbers
(Most common isotopes)
Hydrogen
1
Neutrons = mass # – protons
H
For Hydrogen 3:
3 (mass #) – 1 (atomic #) = 2 (neutrons)
1.01
1, 2, 3
Hydrogen 3 has 2 neutrons.
If the number of electrons equals the number of
protons the atom is neutral. If not, it is an ion.
Ions and Neutral Atoms
Ions
Neutral Atoms
11p
12n
1 proton = Hydrogen
1 proton (+1)
1 electrons (–1)
+1 –1 = 0
neutral atom
Mass # = protons + neutrons
2 protons = Helium
2 proton (+2)
2 electrons (–2)
+2 –2 = 0
neutral atom
attract
8p
8n
Positive and
negative
ions attract
each other.
8 protons = Oxygen
8 p –10e = –2
negative ion: O –2
11 protons = Sodium
11 p –10e = +1
positive ion: Na+1
Adding
andwill
removing
electrons
from
atom
changes
charge.
Electrons
want fill up
inner orbits
firstan
to get
as close
to theits
nucleus
as possible.
Electrons
in Ions Because
Electrons Orbits
They also
to stayhas
as far
away fromcharge,
each other
as possible.
anwant
electron
a negative
when
you add electrons, the ion is negative.
When you remove electrons, the ion is positive.
+
Opposites
attract
proton
–
Like charges
repel
–
–
electron
2 electrons
lithium
lithium
The # of elements
in a row = # of
electrons in a level.
# rows = # of
energy levels.
End of a row
means a full
energy level.
1st level
2nd level
3rd level
3p
3n
3p
3n
Incorrect! - The electrons will
fill up the inner levels first.
The first level takes 2 electrons.
cstephenmurray.com
Correct! - Inner orbit
is full (with 2);
one outer electron.
4th level
Sodium starts the
3rd electron levels.
Neon has 2 filled
energy levels.
1st row has 2 elements, so the first
energy level can hold 2 electrons.
Legal copying of this worksheet requires written permission.
Copyright © 2006, C. Stephen Murray
Name: _____________________
SN: ______
Date: Friday, October 17
Period: _____________________
1. Isotope
____
A. An average of all the isotopes; the
mass of average atom.
Give abbreviations and number of protons
Calcium (Ca)
2. Atomic mass __ B. An atom with an equal number of
electrons and protons.
3. Atomic # ____ C. An atom with more or less electrons
than protons.
4. Neutral atom __ D. A variation of an element with a
different number of neutrons.
5. Ion ____
E. Total number of protons and neutrons
in the nucleus.
6. Mass # ____
F. Number of protons; determines the
element.
7 protons and 10 electrons.
15 protons and 15 electrons.
35 protons and 37 electrons.
89 protons and 89 electrons.
Neutral atom or ion?
Neutral atom or ion?
Neutral atom or ion?
Neutral atom or ion?
Give the element abbreviation and charge.
5 protons and 2 electrons: Element: B Charge:
20
.
Boron (____) __________
Potassium (____)________
Selenium (____) _______
Copper (____) __________
Silver (____)___________
Zirconium (____) _______
Mercury (____) ________
Which of the following are isotopes? (Highlight or circle)
Element A: 15 protons; 15 electrons; 16 neutrons
Element B: 14 protons; 16 electrons; 14 neutrons
Element C: 15 protons; 18 electrons; 15 neutrons
Element D: 16 protons; 18 electrons; 15 neutrons
Element E: 15 protons; 18 electrons; 14 neutrons
Sulfur 32 has 16 protons and 16 neutrons. (32 – 16p = 16n)
Magnesium 25 has ___ protons and _________ neutrons.
Carbon 14 has ___ protons and _________ neutrons.
+3
.
Lithium 7 has ___ protons and _________ neutrons.
16 protons and 18 electrons: Element:
Charge:
.
35 protons and 36 electrons: Element:
Charge:
.
Chlorine 35 has ___ protons and _________ neutrons.
12 protons and 10 electrons: Element:
Charge:
.
Fluorine 19 has ___ protons and _________ neutrons.
What’s wrong with this
picture of an atom?
neutron
Oxygen 16 has how many neutrons?
proton
Beryllium 8 has how many neutrons?
electron
This picture is supposed to
be of a neutral atom. Fix it.
Unit 2:6
Boron 11 has how many neutrons?
For
each
positive
ions2 listed
column
1,
Which
rowof
is the
Lithium
(Li) in?
. It has in
electrons
in levels
1 and
2. periodic table to find in column 2 the total
use
the
number
ofiselectrons
that(___)
ion in?
contains.
same
Which row
phosphorous
____ So, The
phosphorous
answer
may
be
used
more
than
once
has electrons in which electron levels?
10p
11n
Which
___ 1.row
Alis+3calcium (___) in? ____ So, calcium
A.has
2
electrons in +3
what levels?
___ 2. Fe
What is wrong with this
picture of an atom?
8p
7n
What is wrong with this
picture of an atom?
7p
7n
B.10
Which
___ 3.row
Mgis+2argon (___) in? ____ So, argon has
C. electrons
21
in what levels?
+2
___ 4. Sn
D. 23
___ 5. Co+2
E. 24
Argon (___)+3is at the end of row ___. So argon has ____
___ 6. Co
F. 25
full electron+1levels.
___ 7. Li
G. 36
Helium
(___)
is
at
the
end
of
row
___.
So
helium
+3
___ 8. Cr
H.has
48____
full electron+1
levels.
___ 9. Rb
I. 76
+2
Xenon
(___)
is
at
the
end
of
row
___.
So
xenon
___ 10. Pt
J.has81____
full electron levels.
How many full electron levels does Calcium have?
How many full electron levels does Sulfur have?
cstephenmurray.com
Legal copying of this worksheet requires written permission.
Copyright © 2006, C. Stephen Murray