1. CHEM 5013 Applied Chemical Principles
Chapter Two
Professor Bensley
Alfred State College

2. Chapter Objectives
Define the terms atom, molecule, isotope, ion and functional group in your own words.
Describe the nuclear model for the atom and identify the numbers of protons, electrons, and neutrons in a particular isotope from its chemical symbol.

3. Chapter Objectives
Calculate the atomic mass of an element from the masses and abundances of its isotopes.
Determine the number of atoms in a molecule from its chemical formula.
Describe the arrangement of elements in the periodic table and explain the usefulness of the table.

4. Chapter Objectives
Understand the basic differences between organic and inorganic chemistry.
Use standard chemical nomenclature to deduce the names of simple inorganic compounds from their formulas or vice versa.

5. Review
What is an element?
What is an atom?
What is a compound?

6. Atomic Structure of Matter
Matter is composed of:
Parts of the Atom:

7. “Nuclear Structure” of the Atom
Protons
Neutrons

8. Real Nuclear Structure of the Atom
Electrons are depicted as clouds of negative charge surrounding the nucleus.

9. Nuclear Structure of the Atom
Atomic Number (Z):

10. Nuclear Structure of the Atom
Mass number (A):
+ =
Number of number of = Mass
Protons neutrons Number

12. Atomic Number and Mass Number
Atomic Mass Units (amu)
1 amu =
Protons and neutrons nearly times more massive than electrons
Proton =
Neutron =
Electron =

13. Nuclear Structure of the Atom
Proton
Neutron
Electron
Symbol
Location
Charge
Mass

14. Isotopes
Isotopes:
Isotopic abundance:

15. Isotopes
Mass spectrometers can measure the mass of atoms and isotopes.

16. Isotopes
Mass spectrum for carbon isotopes.

17. Atomic Symbols
We use atomic symbols to represent atoms of the different elements.
Usually one or two letters
If two letters, Capital followed by lowercase
Examples:

18. Atomic Symbols Atomic Symbol (Nuclide Symbol) Example:
Chlorine exists as two isotopes: chlorine-35 and chlorine-37
Written as:
What is the difference between chlorine-35 and chlorine-37?

19. Atomic Symbols

20. Atomic Masses

21. Atomic Masses Fractional Abundance: Relative atomic mass: Carbon-12 =
Weighted average mass =

22. Atomic Masses
Calculate the atomic mass of boron, B, from the following data:
ISOTOPE ISOTOPIC MASS (amu) FRACTIONAL ABUNDANCE B B

23. Periodic Table of the Elements
1869 – Dmitri Mendeleev
Found that when elements were arranged in order of atomic weight, they could be placed in horizontal rows, one row under the other, so that the elements in vertical columns have similar properties!

24. Periodic Table of the Elements

25. Periods Referred to by numerical designations
Top row is period 1, etc.
The two rows that normally appear separately at the bottom of the chart actually belong within the body of the chart in periods 6 and 7.

26. Groups
Each group is identified by a numerical designation. Over the years, two different numbering systems have been developed.
Group (Family) Names

27. Periodic Table of the Elements
Do you see the heavy staircase in the periodic table?

28. Ions Ions: What is the charge on an electron?
So what happens to the net charge if you take one electron away? Add one on?

29. Ionic Substances Two possibilities for formation of ions:
Add an electron
Lose an electron

30. Ions

31. Ions
Two fundamental ideas about electric charge.

32. Ionic Bonding
Two depictions of a NaCl crystal.

33. Chemical Formulas Chemical formula:
Convey relative proportions of atoms of the different elements in the substance.
Examples:

34. Molecular Formulas Two types of Chemical Formulas: Molecular Formulas
Ionic Formulas

35. Ionic Formulas Ionic formula:
What is the overall charge on an ionic compound?

36. Ionic Formulas
What is the formula of magnesium nitride, which is composed of the ions Mg2+ and N3-?
What is the formula of calcium phosphate which is composed of the ions Ca 2+ and (PO4)3-?
What is the formula of magnesium oxide which is composed of the ions Mg2+ and O2-?