Download Atoms and Elements Day 2

The Atom
Isotopes and Ions
Isotopes
Atoms with the same number of protons, but
different numbers of neutrons
Atoms of the same element (same atomic
number) with different mass numbers
Example: Two isotopes of chlorine
35Cl
37Cl
17
17
chlorine - 35
(contains 18 neutrons)
chlorine – 37
(contains 20 neutrons)
Practice Exercise
Naturally occurring carbon consists of three
isotopes, 12C, 13C, and 14C. State the number
of protons, neutrons, and electrons in each of
these carbon atoms.
12C
6
13C
14C
6
6
#p _______
_______
_______
#n _______
_______
_______
#e _______
_______
_______
Practice exercise
Write the atomic symbols for atoms with
the following:
A. 8 p+, 8 n, 8 e-
_________
B. 17p+, 20n, 17e- _________
C. 47p+, 60 n, 47 e-
_________
Isotopes
Oxygen – 16 and Oxygen – 18
Phosphorous – 31 and Phosphorous – 32
Cobalt – 59 and Cobalt – 60
Ions
Ionization – the process of adding or removing
electrons from an atom or group of atoms
Ion – an atom or group of atoms that has lost or
gained one or more electrons and therefore has
a net electric charge.
Cations
When atoms lose
electrons, they
form cations
and will have a
positive charge.
Anions
When atoms gain
electrons, they
form anions and
will have a
negative charge.
Practice exercise
An atom of zinc has a mass number of 65. what
is the number of protons?
1) 30
2) 35
3) 65
What is the number of neutrons in an atom of
zinc?
1) 30
2) 35
3) 65
What is the mass number of a zinc isotope with
37 neutrons?
1) 37
2) 65
3) 67
Practice Problems
Ion
N3Al3+
K+
Sr2+
Mn2+
Cl-
Protons
Neutrons
Electrons