© 2003 mark s. davis chapter 2 atomic structure. © 2003 mark s. davis law of conservation of mass...

© 2003 Mark S. Davis

Chapter 2

Atomic Structure


Law of Conservation of Mass

• Mass can be neither created nor destroyed in chemical reactions.

• The total mass of the products is the same as the total mass of reactants.


Law of Constant Composition

• Water is water, no matter where you get it; H2O is H2O

• The elements in a compound are present in a fixed and exact proportion regardless of the source.


Percent Composition

• Percent by mass of an element in a compound.– I.e. water


Practice

• Determine the percent composition of.


Dalton’s Theory• All matter is composed of atoms.• The atoms of any one element are

identical.• Atoms of different elements have

different masses.• Compounds are atoms combined with

other atoms.• In reactions, atoms are exchanged to

form new compounds.


Atomic masses

• Relative.

• Based on carbon-12.

• Isotopes.

• Mass numbers on Table reflect abundance of isotopes.


Practice

• Suppose in one crate there were 4500. g of oranges weighing 150. g each. How many oranges are in the crate?


Atomic Number

• Tells you…


Structure

• Protons

• Neutron

• Electron


Calcium

• Atomic number =

• What is the charge?


Ions

• Gain or lose electrons– ONLY ELECTRONS!


Calcium Ion

• What is the charge


Isotopes

• Identified by mass number

• C-12, C-13

• Alternate notation– Mass number above (superscript)– Atomic number below (subscript)


Average Atomic Mass

• What is the average mass of element Q? The abundances are:


Periodic Table

• Label appropriately…

• Properties of elements

• Tables 2.2 and 2.3

• Explained by organization in atom


Electromagnetic Radiation

• Electromagnetic spectrum


Emission Spectra

• See figure 2.10, p 51

• Fireworks


Absorption Spectra

• Radiation absorbed by atoms


Model of the Atom

• Niels Bohr

• Explains Hydrogen


Quantum numbers

• Tell you how the electrons behave


Principal Quantum Number

• The first quantum number


Azimuthal Quantum Number

• The second quantum number

• Tells you the 3-D region in which you find electrons (orbital)

• Symbolized by l


Magnetic Quantum Number

• The third number

• Tells you the orientation of the orbital in 3-D space


Spin Quantum Number

• Final quantum number

• Tells you in which direction the electron spins

• Electrons behave like little magnets (spin gives magnetism)

• Value of + or – ½ or…


Putting it all together

• Table 2.6 and 2.7

• Orbital arrangement on the periodic table

• Electron configuration

• Aufbau principal– “Building up’


Pauli Exclusion Principal

• No more than two electrons per orbital


Hund’s Rule

• Electrons (little magnets) repel each other if they have the same spin


Pictures of Orbitals

• A d orbital


Chapter 1

• States of matter

• Classification of substances– Mixtures– Pure substances, etc

• Methods of separation of mixtures


Chapter 1

• Measurement

• Units

• Conversions

• Significant figures, calculations


Chapter 1

• Density and calculations

• Temperature and conversions

• Specific heat and calculations


Chapter 2

• Dalton’s ideas

• Percent composition

• Interpretation of the table– Masses, atomic number, etc

• Isotopes and average weighted mass


Chapter 2

• Quantum numbers

• Orbitals

• How to put them together…

© 2003 mark s. davis chapter 2 atomic structure. © 2003 mark s. davis law of conservation of mass...

Documents

quantum numbersorbitalshow

lmagnetic quantum numberthe

mass numbers

mass numberc

atoms of different elements

atomic massesrelative

average mass of element

total mass of reactants