1. The Elements – Part 2
Getting Specific

2. Now that we know that all the elements are listed on The Periodic Table of the Elements just what information is given to us in those little boxes? Ti
Titanium
47.867 22 14 Si
Silicon

3. Ti 22 Atomic number Symbol Element name Atomic mass or Atomic weight
Titanium
47.867 22
Element name
Atomic mass or Atomic weight

4. Ti Atomic number 22 Tells you two things:
How many protons (+) are in one atom.
How many electrons (-) are in one atom.
For an atom to be electrically neutral there must be the same number of + as there are - Ti
Titanium
47.867 22
“PE”

5. Ti Atomic mass (weight) 22 Tells you one thing:
Titanium
47.867 22
Tells you one thing:
The weight of the nucleus.
Remember that the nucleus only has protons and neutrons. If this nucleus has a mass of we know that it is a combination of both protons and neutrons.

6. Ti Atomic mass (weight) 22
Titanium
47.867 22
If there are 22 protons in that nucleus then all we have to do is subtract that from the mass to get the neutrons.
48 (rounded weight of nucleus)
22 (number of protons)
____________
26 neutrons

7. In Summary
To find protons and electrons just look at the atomic number (remember “PE”). Ti
Titanium
47.867 22
To find neutrons subtract the atomic number from the atomic mass.

8. Time for a little practice –
Using your periodic table calculate the number of protons, electrons, and neutrons for the following elements:
helium
sodium
iron
zirconium
Protons: 2
Electrons: 2
Neutrons: 2
Protons: 11
Electrons: 11
Neutrons: 12
Protons: 26
Electrons: 26
Neutrons: 30
Protons: 40
Electrons: 40
Neutrons: 51

9. Let’s do it in reverse –
What element is pictured here?
Nitrogen