Do Now. Draw a bohr model for Boron. Do Now. Describe what makes a source reliable and accurate?. Atomic Number, Atomic Mass, and Isotopes. Happy Pt Tuesday!!!!. By the end of the class today I will be able to…. Student will understand the symbol for an isotope.
Happy Pt Tuesday!!!!
If we made a scale model of an atom and wanted to use Cowboy Stadium as our electron cloud, the nucleus of the atom would be the size of the eraser on the end of your pencil. An electron would still be smaller than the point on a straight pin.
Number of protons/ Atomic Number
All atoms of the same element have the same number of protons
n0Number of Protons, Neutrons, & Electrons
# Protons =
How to Use the Periodic Table
# Electrons =
# Neutrons =
Example 1: Argon
X: element symbol
A: Mass Number
#protons + # neutrons in the nucleus
Always larger than Z
Z: Atomic number
How many protons are in the isotope 54Cr? (Chromium-54) (add it to your table)
24 (like every atom of Chromium)
How many neutrons are in the isotope 42Ca? Number or protons? (add it to your table)
How many electrons are in the isotope 23Na? Write it’s nuclear notation (add to table)
Atomic Mass Unit
1 amu= 1.66 x 10-24 g
Mass of n0
Mass of p+
Example 7: Mass of Beryllium
Mass of e-
Drawing or TraitsiSOTOPE
What sub-atomic particle(s) are the same for the isotopes of Helium?
What sub-atomic particle(s) are different for the isotopes of Helium?
Are these four isotopes neutral? Why or Why not?
Write the following as an isotope symbol…
Number of Neutrons = A-Z
How many neutrons are in the isotope 48Ti?
How many electrons are in the isotope 23Na? (you can assume the atom is neutral)