Atomic Structure. Elements and Atoms Element- a pure substance made up of only one type of atom....
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Transcript of Atomic Structure. Elements and Atoms Element- a pure substance made up of only one type of atom....
Atomic Atomic
StructureStructure
Elements and Atoms• Element- a pure substance made up of
only one type of atom.
•Atom- smallest unit of an element that maintains the properties of
that element.
Types of Elements
1. Metals- good conductor, lustrous, malleable, ductile. Left of zigzag line.
2. Nonmetals- poor conductor, most are gases at room temperature. Right of zigzag line.
3. Metalloids- characteristics of metals and nonmetals. On the zigzag line.
Inside the Atom
Protons: 1) positively charged particles 2) define the element 3) equal to the atomic number
Neutrons: 1) neutrally charged particles2) approximately the same
size as protons (a bit more)
Electrons: 1) negatively charged particles2) A lot smaller than the
protons or neutrons
On the Periodic Table On the Periodic Table you see…you see…
Atomic Number Atomic Symbol
Avg. Atomic Mass
Element
Understanding the Periodic Understanding the Periodic TableTable
Atomic Number:Atomic Number: the unique number of an the unique number of an element defined by the number of protonselement defined by the number of protonsEquals the number of electrons Equals the number of electrons
Atomic Symbol:Atomic Symbol: an abbreviation of an an abbreviation of an elementelement
Average AtomicAverage Atomic MassMass: the average of : the average of mass numbers of the isotopes of an mass numbers of the isotopes of an elementelement
Isotopes • atoms of the same element with
different masses (mass numbers)• same number of protons• different number of neutrons
Mass Number• mass of protons + mass of neutrons•This number can vary between atoms This number can vary between atoms of an element.of an element.
Three Isotopes of Hydrogen:Three Isotopes of Hydrogen:
Protium (99.9885%), Deuterium (0.0115%), Protium (99.9885%), Deuterium (0.0115%), TritiumTritium
Average atomic mass: 1.0079 Average atomic mass: 1.0079
QuestionQuestion
All isotopes of hydrogen containAll isotopes of hydrogen contain
a. one neutrona. one neutron c. one protonc. one proton
b. two electronsb. two electrons d. two nucleid. two nuclei
Sample
Mass Spectrometer
Electron Field Accelerator
Charged Particle Beam
Magnet
Heaviest Particles
Lightest Particles
Detector
According to a mass spectrometer experiment, the following data is obtained using a Nitrogen sample:
99.64% atoms are N 14 isotopes 0.36% atoms are N 15 isotopes
What is the weighted average?
Two ways to represent Isotopes of an atom:1) Hyphen Notation:
- element name – mass # Ex: hydrogen - 3
2) Nuclear symbol
mass = upper left hand number# protons = lower left hand number
Deuterium = 21H
Tritium = 31H
Given the nucleus below:
What is the mass number of this element? Which element is this?
The size of the nucleus:The size of the nucleus:
QuestionQuestion
Protons within a nucleus are Protons within a nucleus are attracted to each other byattracted to each other by
a. nuclear forcesa. nuclear forces
b. opposite chargesb. opposite charges
c. their energy levelsc. their energy levels
d. electron repulsiond. electron repulsion
QuestionQuestion
The nucleus of an atom has all The nucleus of an atom has all of the following characteristics of the following characteristics EXCEPT that itEXCEPT that it
a. is positively chargeda. is positively charged
b. is very denseb. is very dense
c. contains nearly all of the atom's massc. contains nearly all of the atom's mass
d. contains nearly all of the atom's volumed. contains nearly all of the atom's volume
The Charges:The Charges:
Proton: +1Proton: +1 mass = 1 amumass = 1 amuNeutron: 0 charge Neutron: 0 charge mass = 1amumass = 1amuElectron: -1Electron: -1 mass = .00055 amumass = .00055 amu
Atomic Mass Unit (amu)Atomic Mass Unit (amu)
1 atom chosen arbitrarily for the standard1 atom chosen arbitrarily for the standardcarbon-12 has a mass of 12 amucarbon-12 has a mass of 12 amu1amu = exactly 1/12 the mass of a 1amu = exactly 1/12 the mass of a
carbon-12 atomcarbon-12 atomThe atomic mass of any atom is The atomic mass of any atom is
determined by comparing it to carbondetermined by comparing it to carbon
How many protons, electrons & How many protons, electrons &
neutrons are in Carbon 14?neutrons are in Carbon 14?
Protons: Always 6 in carbonProtons: Always 6 in carbonElectrons: Same as protons, or 6Electrons: Same as protons, or 6Neutrons = Mass# - protonsNeutrons = Mass# - protonsNeutrons: 14 - 6 = 8 neutronsNeutrons: 14 - 6 = 8 neutrons
QuestionQuestion
An aluminum isotope consists of 13 An aluminum isotope consists of 13 protons, 13 electrons, and 14 protons, 13 electrons, and 14 neutrons. Its mass number isneutrons. Its mass number is
a. 13a. 13 c. 27c. 27
b. 14b. 14 d. 40d. 40
QuestionQuestion The atomic mass listed in the periodic The atomic mass listed in the periodic
table is the:table is the:
a. average atomic mass.a. average atomic mass.
b. relative atomic mass of the most b. relative atomic mass of the most
abundant isotope.abundant isotope.
c. relative atomic mass of the most c. relative atomic mass of the most
stable radioactive isotope.stable radioactive isotope.
d. mass number of the most abundant d. mass number of the most abundant
isotope.isotope.