Download File - Ms. Gutierrez`s Chemistry Website

ChemCatalyst
10/23/15
Today you need your notebook and Laptop. Open the
PowerPoint on the weebly.
In your notebook answer the following questions:
1. What two particles does the nucleus
contain?
2. Which subatomic particle has the
smallest mass?
3. What is the electrical charge of a
proton? Electron? Neutron?
The Atom:
Calculating Protons,
Neutron, and Electrons
Chemistry/Pre-AP Chemistry
Ms. Lizette Gutierrez
Austin High School
Periodic Table Information
Atomic Symbol
• Atomic Symbol
• Shorthand notation of one (uppercase) or two letters
(1 uppercase and 1 lowercase) for an element
• Derived from the scientific names of the chemical
elements
• S for sulfur
• Cl for chlorine
• Zn for zinc
• Some date back to Latin names
• Au (aurum) for gold
• Pb (plumbum) for lead.
• Others are named for people or places
• Es, Einsteinium for Einstein
• Cf, Californium for California
• Md, Mendelevium for Mendeleev
Periodic Table Information
Atomic Number
• Discovered around 1913 by a
Scientist name Henry Moseley
• Atomic Number is the number of
protons in the nucleus of an atom.
• The atoms of each element differ
from the atom of the element before
it by one proton.
• In atoms that are electrically neutral,
atomic number also is the number of
electrons.
Periodic Table Information
Atomic Mass
• Atomic Mass (mass number)
– the mass of an individual atom of a
particular element.
– Units are in amu (atomic mass units)
• It was determined that the nucleus accounts
for almost all the mass of the atom.
• Both the proton and the neutron are about
2,000 times more massive than a tiny electron.
Using the Periodic Table to Calculate Protons,
Neutrons, and Electrons of an Atom
• Protons = Atomic Number
• Electrons = Atomic number (assume neutral atom)
• Neutrons =
You can estimate number of neutrons in an atom by taking the atomic mass
(rounded to the nearest whole number) minus the atomic number.
Classroom Example #1
Calculate the Number of p, n,
and e for Lithium?
Number of protons = 3
Number of electrons = 3
Number of neutrons
7 (6.941) – 3 = 4
Classroom Example #2
# protons =
# electrons =
12
12
# neutrons = 24 -12=
12
Classroom Example #3
# protons =
# electrons =
18
18
# neutrons = 40 -18=
22
Classroom Example #4
# protons =
# electrons =
36
36
# neutrons = 84 -36=
48