Isotopes and Ions
Isotopes
• Atoms of the same element can have different
numbers of neutrons.
• different mass numbers.
• called isotopes.
• Boron-10 (10B) has 5 p and 5 n
• Boron-11 (11B) has 5 p and 6 n
11B
10B
Symbols
• Contain the symbol of the element, the mass
number and the atomic number.
Symbols
• Contain the symbol of the element, the mass
number and the atomic number.
Mass
number
Atomic
number
X
Naming Isotopes
• Put the mass number after the name of the
element.
• carbon- 12
• carbon -14
• uranium-235
Symbols
• Find the
– number of protons
– number of neutrons
– number of electrons
– Atomic number
– Mass Number
– Name
24
11
Na
Symbols
•
Find the
• number of protons
• number of neutrons
• number of electrons
• Atomic number
• Mass Number
• Name
80
35
Br
Symbols
•
if an element has an atomic number of
34 and a mass number of 78 what is the
• number of protons
• number of neutrons
• number of electrons
• Complete symbol
• Name
Symbols
•
if an element has 91 protons and 140
neutrons what is the
• Atomic number
• Mass number
• number of electrons
• Complete symbol
• Name
Symbols
•
if an element has 78 electrons and 117
neutrons what is the
• Atomic number
• Mass number
• number of protons
• Complete symbol
• Name
1. Isotopes are
A. Atoms of the same element with a different
number of neutrons.
B. Atoms or groups of atoms with a positive or
negative charge.
C. Cations
D. Anions
2. The symbol for an isotope contains
A. The atomic number on the top left and the
mass number on the bottom left of the
symbol.
B. The number of electrons.
C. Mice
D. The mass number on top left and the atomic
number on the bottom left of the symbol.
3. When naming an isotope,
A. The mass number comes before the element
name.
B. You just put the elements name.
C. The mass number comes after the element
name.
D. You just put the mass number.
IONS
•
IONS are atoms or groups of atoms with a positive
or negative charge.
•
Taking away an electron from an atom gives a
CATION with a positive charge.
• Adding an electron to an atom gives an ANION with
a negative charge.
• To tell the difference between an atom and an ion,
look to see if there is a charge in the superscript!
Examples: Na+ Ca+2 I- O-2
•
Na Ca I
O
Forming Cations and Anions
• A Cation forms when an
atom loses one or more
electrons.
• CATion: PAWSitive
• An Anion forms when
an atom gains one or
more electrons.
• Anion: A Negative ION
Na Na+ + e-
Cl + e-  Cl-
Forming Cations and Anions
• https://www.youtube.com/watch?v=0q5rP7w
xrDk
Predicting Ion Changes
In general
• metals (Na) lose electrons ---> cations
• nonmetals (Cl) gain electrons ---> anions
Learning Check – Counting
State the number of protons, neutrons, and electrons in
each of these ions.
39 K+
16O -2
41Ca +2
19
8
20
#p+ ______
______
_______
#no ______
______
_______
#e- ______
______
_______