Reading the Periodic Table
Notes #7
Periodic Table of Elements (not notes)
Reading the information (notes)
• Every box in the periodic table represents an element and has at least
3 parts to it
1. Atomic
number
2. Symbol
3. Atomic
mass
1. Atomic number: The number of
protons in the nucleus.
2. Symbol: The one- or two-letter
“short name” for the element.
3. Atomic mass: Number of protons +
neutrons (average).
What isn’t there… (not notes)
• Charge: Charge isn’t shown. Assume that
the number of electrons is equal to the
number of protons
• Number of neutrons: Not shown because
it is possible to figure out the number of
neutrons with the following equation:
(Rounded atomic mass) – (Atomic number)
Atomic Mass is a Decimal…? (not notes)
• The atomic mass shown on the periodic
table is actually an average
• While all atoms of the same element
have the same number of protons they
don’t necessarily have the same number
of neutrons. These are called isotopes
Isotope
Practice (not notes, on sheet)
1
H
1.00794
• Atomic number:
• Atomic mass:
• Atomic symbol:
• # of Protons:
• # of Neutrons:
• # of Electrons:
Practice (not notes, on sheet)
1
H
1.00794
• Atomic number: 1
• Atomic mass: 1.00794
• Atomic symbol: H
• # of Protons: 1
• # of Neutrons: 0
• # of Electrons: 1
Practice (not notes)
16
S
32.066
• Atomic number:
• Atomic mass:
• Atomic symbol:
• # of Protons:
• # of Neutrons:
• # of Electrons:
Practice (not notes)
16
S
32.066
• Atomic number: 16
• Atomic mass: 32.066
• Atomic symbol: S
• # of Protons: 16
• # of Neutrons: 16
• # of Electrons: 16