1. Properties of Atoms. 2. Atomic Structure Goals. SC3 Students will use the modern atomic theory to explain the characteristics of atoms. a. Discriminate between the relative size, charge, and position of protons, neutrons, and electrons in the atom.
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Properties of Atoms
Atomic Structure Goals
SC3 Students will use the modern atomic theory to explain the characteristics of atoms.
a. Discriminate between the relative size, charge, and position of protons, neutrons, and electrons in the atom.
b. Use the orbital configuration of neutral atoms to explain its effect on the atom’s chemical properties.
c. Explain the relationship of the proton number to the element’s identity.
d. Explain the relationship of isotopes to the relative abundance of atoms of a particular element.
e. Relate light emission and the movement of electrons to element identification.
This will be our FOCUS
Bohr Model- electrons are found only in specific circular paths, or orbits, around the nucleus.
Electron Cloud Model: Probable locations of electrons.
Quantum Mechanical Model: Mathematical model describing the behavior of electrons and energy of electrons in various locations around the nucleus.
What makes one element different from another element?
Number of protons.
Electrons are found in the
surrounding the nucleus.
Each Energy Level Can Hold A Certain Number of Electrons!
Only TWO on the first level!
Different atoms have different numbers of electrons!
Each Energy Level Can Hold A Certain Numbers of Electrons!
Eight on the 2nd
The # of Protons determines the identity of an element. All elements have different number of protons.
So, this model is based on probability rather than certainty.
2nd quantum number= l
# of sublevels
# of sublevels (shapes)
Orbital Filling Diagrams (3 rules)
NameAtomic NumberElectron Configuration
Isotopes are atoms that have the same number of protons and differonly in the number of neutrons.
Most isotopes are stable but radioactive isotopes are unstable and break down into more stable forms byemitting particles and energy (radiation).
Radiation can be detected, so radioactive isotopes are useful as labels in scientific research and medical diagnostic procedures.
Let’s Do some practice problems
Isotopes Mass of Isotope Abundance
24Mg =24.0 amu 78.70% = ______
25Mg = 25.0 amu 10.13% = ______
26Mg = 26.0 amu 11.17% = ______
Atomic mass (average mass) Mg = 24.3 amu
What is the Mole?
A counting number (like a dozen)
Avogadro’s number (NA)
1 mol = 6.02 1023 items
Amedeo Avogadro (1776-1856)
Molar Mass Examples
2.25 mol Fe
55.85 g Fe
1 mol Fe
= 126 g Fe
5.0 g Ca
1 mol Ca
40.08 g Ca
= 0.12 mol Ca
Mole Day is October 23rd!