Atoms What are we going to study about the atom? History Structure Properties Forces

Atomic Structure 1.What is an atom composed of? 2. What subparticle(s) are responsible for an atom’s charge? 3. What subparticle(s) are responsible for an atom’s mass? 4. Illustrate an atom, identifying the subparticles and their location within the atom.

Atomic Structure Subatomic Particle symbolchargeMass (g) mass (amu) protonp x electrone x neutronn0n x

Distinguishing Atoms 1.Draw the atom below and identify the following: electrons, protons, neutrons, electron cloud, nucleus, and energy levels. 2.What distinguishes one element’s atom from another element’s atom? education.jlab.org

What distinguishes each element below from one another?

Distinguishing Atoms

Atomic number The number of protons within an atom’s nucleus. An atom’s I.D. Atoms of the same element always have the same number of protons. What do you notice about the atomic numbers on the periodic table?

An Atom’s Mass Mass number : The mass of a single atom. Sum of the p+ and n 0 within an atom. Unit: atomic mass unit (amu) The mass number is NOT the same as Atomic Mass

Atomic Structure Subatomic Particle symbolchargeMass (g) mass (amu) protonp x electrone x neutronn0n x

Element’s Subatomic Differences ElementAtomic Symbol Atomic Number Mass # (amu) # of p+# of n 0 # of e-

Neutral Atoms Most matter in nature is neutral. (Doesn’t shock us!) This means the atoms making up the matter is neutral. What are the two charged subatomic particles? p+ and e- For an atom to be neutral the # of p+ = # of e-.

Elements Quiz When: Thursday What: First 20 elements on the periodic table. Know: symbols and names

Atoms What are we going to study about the atom? History Structure Properties Forces

Isotopes What is an isotope? Atoms of the same element that have different number of neutrons. Also have different number of neutrons.

Common Isotopes of Carbon C-12 C-13 # of p+, n 0, e-?

Atomic Structure History, Structure and Properties of the Atom

Quiz: History of the Atom Who is given credit for the earliest model of the atom? Explain Thomson’s Plum Pudding model of the atom. What did Rutherford’s model contribute to the atom? What did Bohr’s model contribute to the atom?

History of the Atom Great Thinkers (2,000yrs. Ago) Age of Reason and Thought Democritus vs. Aristotle view on the make-up of matter.

Democritus(400b.c.) Greek Philosopher 1) Observed matter to be made up of atoms. 2) Atoms are the smallest form of matter. 3. Atoms cannot be broken down. 3) The types of atoms in matter determine its properties.

Aristotle: Greek Philosopher (300b.c.) Aristotle observed matter to be made from four things: air, earth, fire and water.

John Dalton’s Atomic Model

1.Atoms are the building blocks of all matter. 1.Atoms cannot be subdivided. 2.Each element has the same kind of atoms. 3.In a compound, the different atoms chemically combine in the same way (fixed composition). 4.Atoms cannot be created or destroyed just rearranged. Dalton’s Atomic Theory

John Dalton’s Atomic Model English school teacher Proved Democritus atoms hypothesis using the scientific method. His conclusions produced: Dalton’s Atomic Theory

Thomson’s Plum Pudding Model

Thomson’s Cathode Tube Experiment l-esperimento-piu-bello-della-fisica.bo.imm.c...

Subatomic Particle: Electron J.J. Thomson (pg. 105) 1897 discovered electrons in gas atoms using a cathode ray tube. Determined electrons have a negative charge. Electrons have the same charge in all atoms. Robert Millikan: Determined the mass of the electron to be very tiny.

J. J Thomson’s Plum Pudding Model If atoms are made of electrons how come most matter does not shock us? Atoms must have positive particles, too. He proposed the Plum Pudding Atomic Model An atom is equally made up of positive and negative particles.

Goldstein’s Cathode Tube Experiment reich-chemistry.wikispaces.com chemed.chem.purdue.edu He discovered protons using a cathode ray tube. Observe particles moving in the opposite direction.

Subatomic Particles: Protons 1886 Eugen Goldstein observed particles traveling in the opposite direction of the cathode rays(electrons). He knew these particles must be (+) charged. They were called protons. Protons charge is the same for all atoms Protons have a significant mass compared to the electron.

Rutherford’s Model of the Atom green-planet-solar-energy.com

Rutherford’s Gold Foil Experiment

Rutherford’s Conclusion Most of the atom is empty space. Small dense region composed of (+) charged particles. (Nucleus)

Rutherford’s Nuclear Atom Model

What keeps the protons within the nucleus ? (Like particles repel each other) James Chadwick discovers that the nucleus also has neutral particles present. He called them neutrons. Subatomic Particle: Neutron

Chadwick’s Experiments: Neutron nobelprize.org

Bohr’s Model of the Atom

Bohr’s Model of the Atom

Current Atomic Model blogs.stsci.edu Erwin Schrodinger

Current Atomic Model blogs.stsci.edu science.howstuffworks.com Erwin Schrodinger

Current Atomic Model blogs.stsci.edu Erwin Schrodinger

Types of electron paths around nucleus

GenChem: Infinite Campus Update Corrections to Measurement and Matter Exam Subatomic Structure Worksheet (10pts.) History of Atom Quiz (4pts.)

preAPChem: Infinite Campus Update Corrections to Measurement and Matter Subatomic Structure Worksheet (10pts.) History of Atom Quiz (4pts.) Atomic Structure Quiz (20pts.)

Bell Ringer: History of Atom Atomic ModelIllustrationDescription Dalton’s Model Thomson’s Model Rutherford’s Model Bohr’s Model Schrodinger’s Model (current model)

Isotopes and Atomic Mass What is an isotope? What does an isotope notation tell you? An element’s isotopes are used to calculate the atomic mass of an element.

Atomic mass: The average mass of all the element’s isotopes present within a naturally occurring sample of matter. Weighted average mass. (unequal distribution of isotopes in sample of matter) Located on the periodic table. How do you calculate atomic mass? 1. Multiply the mass # of each isotope by its natural abundance ( common occurrence) in decimal form. 2. Add all the isotopes products together. Isotopes and Atomic Mass

Element’s Atomic Mass (average mass) Carbon (C) has two isotopes: Carbon-12 has a natural abundance = 98.89% Carbon-13 has a natural abundance = 1.11% Carbon’s atomic mass: Isotope’s mass number x natural abundance = C-12: C-13:

Element’s Atomic Mass 1.Atomic Mass of Au: amu 2.Atomic Mass of Fe: amu 3.Atomic Mass of N: amu 4.Atomic Mass of Si: amu

Kandium Lab Purpose: To analyze Kandium’s isotopes and calculate the atomic mass of this “new” element.

Chemistry Assignments: Kandium Lab due-turn in tray. Please check infinite campus for missing assignments- all make-up work is due by tomorrow for partial credit. Quiz tomorrow over Atoms: (models, subparticles, isotopes, and atomic mass calculations)

Bell Ringer: Atomic Models a.What are the advantages to atomic models in science? b. What are limitations to atomic models in science?

Atomic Models Dalton’s Atomic Model Thomson’s Plum Pudding Model Rutherford’s Nuclear Model Bohr’s Planetary Model Schrodinger’s Atomic Model (current model)

ElementIsotopeNatural Abundance Atomic #Mass # p+n0e- LithiumLi LithiumLi Element’s Isotopes and Atomic Mass Lithium’s Atomic Mass:

Mass Number vs. Atomic Mass 1.What is the difference between mass number and atomic mass? 2.Complete the table below on Iodine’s neutral isotopes Iodine’s Isotopes Natural Abundance (%) mass number p+nono e- I I I Calculate the atomic mass of Iodine. Show work and include units.

Atomic Structure and Properties If most of the atom is empty space, why doesn’t matter pass through one another? What keeps the protons from leaving the nucleus and being drawn towards the electrons?

Atomic Properties If most of the atom is empty space, why doesn’t matter pass through one another? spiff.rit.edu

Atomic Forces Electrostatic Forces : -Forces between charged particles. Nuclear Forces: Forces that hold the nucleus together.

Atomic Forces Electrostatic Forces : -Forces between charged particles. Types of electrostatic forces: a.Attractive: (p+ and e-) b.Repulsion: (p+ and p+ e- and e-) Nuclear Forces: Forces that holds p+ and n 0 together in nucleus. Nucear forces > Electrostatic forces

Bell Ringer: Atomic Forces 1.What are the two primary forces within an atom? 2.Distinguish between these forces. 3.a. Which one of the forces is stronger ? b. Why is this important to the atom’s existence?

Atomic Forces Electrostatic Forces : -Forces between charged particles. Types of electrostatic forces: a.Attractive: (p+ and e-) b.Repulsion: (p+ and p+ e- and e-) Nuclear Forces: Forces that holds p+ and n 0 together in nucleus. Nucear forces > Electrostatic forces