1. Elements, Atoms, and Ions

2. The Language of Chemistry
_________________________-
pure substances that cannot be decomposed by ordinary means to other substances.
Aluminum
Bromine
Sodium

3. The Language of Chemistry
The elements, their names, and symbols are given on the _____________
How many elements are there?

4. The Periodic Table
Dmitri Mendeleev ( )

5. The Atom An atom consists of a _____________________
(of protons and neutrons)
_________________ in space about the nucleus.
Electron cloud
Nucleus

6. Composition of molecules is given by a ______________________
A ______________ is the smallest unit of a compound that retains the chemical characteristics of the compound.
Composition of molecules is given by a ______________________
H2O
C8H10N4O2 - caffeine

7. Copper atoms on silica surface.
An ___________ is the smallest particle of an element that has the chemical properties of the element.
Copper atoms on silica surface.
Distance across = 1.8 nanometer (1.8 x 10-9 m)

8. _________________are composed of atoms and so can be decomposed to those atoms.
The red compound is composed of • nickel (Ni) (silver) • carbon (C) (black) • hydrogen (H) (white) • oxygen (O) (red) • nitrogen (N) (blue)

9. Compounds __________________ __________________ __________________
properties differ from those of individual elements
EX: table salt (NaCl)

10. ATOMIC COMPOSITION ________________________ (p+)
+ electrical charge
mass = x g
relative mass = atomic mass units (amu) but we can round to 1
_________________________ (e-)
negative electrical charge
relative mass = amu but we can round to 0
_________________________ (no)
no electrical charge
mass = amu but we can round to 1

11. IONS
______________________ are atoms or groups of atoms with a positive or negative charge.
Taking away an electron from an atom gives a ______________________with a positive charge
Adding an electron to an atom gives an _____________________ with a negative charge.
To tell the difference between an atom and an ion, look to see if there is a charge in the superscript! Examples: Na+ Ca+2 I- O-2
Na Ca I O

12. Octet Rule = atoms tend to gain, lose or share electrons so as to have 8 electrons
C would like to
N would like to
O would like to
Gain 4 electrons
Gain 3 electrons
Gain 2 electrons

13. IONIC BOND __________________________________________________________________

14. Ionic Bonds: One Big Greedy Thief Dog!

15. COVALENT BOND __________________________________________________________________

16. Covalent Bond
Between nonmetallic elements of similar electronegativity.
_______________________________________________________
Stable non-ionizing particles, they are not conductors at any state
Examples; O2, CO2, C2H6, H2O, SiC

17. ______________________________________________________
NONPOLAR COVALENT BONDS
______________________________________________________
H2 or Cl2

18. 2. Covalent bonds- Two atoms share one or more pairs of outer-shell electrons.
Oxygen Atom
Oxygen Atom
Oxygen Molecule (O2)

19. ______________________________________________________
POLAR COVALENT BONDS
______________________________________________________
H2O

20. Polar Covalent Bonds: Unevenly matched, but willing to share.

21. - water is a polar molecule because oxygen is more electronegative than hydrogen, and therefore electrons are pulled closer to oxygen.