1. Chemistry is the study of… MATTER!!!!!
Matter is any substance which:
Occupies space (i.e. has volume)
Has mass
Found in 3 phases: liquid, solid, gas, (aqueous, dissolved in water)
Can’t be created or destroyed, it only changes form

2. What makes up an atom?
Atoms are made of three types of subatomic particle
Protons (p+) - a positively charged particle located in the nucleus
Neutron (n0) - a neutral (uncharged) particle located in the nucleus
Electron (e-) - a negatively charged particle located outside the nucleus

3. Atomic Number = number of protons (p+)
Atomic Mass = total of protons (p+ ) and neutrons (n0)

4. Ion Formation
When an atom gains or loses electrons they become electrically charged particles called Ions
Metals tend to lose electrons
Positive ions are called CATIONS
Non-metals tend to gain electrons
Negative ions are called Anions

5. How many oxygen ions, O2- are present in each formula:
Counting Atoms
How many oxygen ions, O2- are present in each formula:
MgO
C6H12O6
2 SO2
Mg(OH)2
3Sn(Cr2O7)2 1 6 4 2 42

6. Bohr diagrams show how many electrons appear in each electron shell around an atom.
The first electron shell holds 2 electrons
The second electron shell holds 8 electrons (Stable Octet)
The third electron shell holds 8 electrons
The fourth electron shell holds 18 electrons
The period number = the number of shells in the atom.
Lewis diagrams show only an atom’s valence electrons and the chemical symbol
The column number = the number of valence electrons (electrons in the outer shells in the atom).

7. Forming Compounds
When two atoms get close together, their unpaired valence electrons interact.
Each atom in the compound attempts to have a ‘full’ outer shell of valence electrons.
Unpaired electrons are involved in the bonding and the lone pair electrons are not.

8. Ionic Compounds positive and negative ions. Metal + Non-Metal
Electrons are given and taken.

9. Covalent Compounds negative ions. Non-metal + Non-metal
Share electrons

10. Ionic vs. Covalent Ionic: Metal + Non-metal Ex: Sodium Chloride
NaCl
Covalent
Non-metal + Non-metal
Ex: trinitrogen dioxide
N3O2

11. Naming Simple Ionic Compounds
identify the two elements
aways write the metallic element first.
change the ending of the 2nd element (non-metal) to “ide”
Magnesium bromide
MgBr2 =
K2O =
CaCl2 =
Potassium oxide
Calcium chloride

12. Understanding the Formula Simple Ionic Compounds
Since the OVERALL charge on a COMPOUND (MgO, MgCl2) is ZERO, the positive charges must balance the negative charges.
Therefore, if a metal ion (Mg2+) has a charge of +2, then it can form a compound with either:
ONE non-metal ion (O2-) with an ion charge of MgO
Math: 1(+2) + 1(-2) = 0
TWO non-metal ions (Cl1-) with an ion charge of -1. MgCl2
Math: 1(+2) + 2(-1) = 0

13. Learning Check A. Sodium and Sulfur Na+, S2- Na2S
Write the correct formula for the compounds containing the following elements:
A. Sodium and Sulfur
Na+, S2-
Na2S
B. Aluminum & Phosphorus
Al3+, P3-
AlP
C. Magnesium & Nitrogen
Mg2+, N3-
Mg3N2

14. Names & Formulas for Multivalent Ionic Compounds
It is easy to write the formulas for multivalent ionic compounds, because they tell you their combining capacities.
Example
1) Gold (I) chloride
Au+1 Cl-1
AuCl
PbO2
2) Lead (IV) oxide
Pb+4O-2

15. Naming for multi-valent compounds

16. Learning Check CuO (Cu2+ ) copper (II) Oxide
FeCl3 (Fe3+) iron (III) chloride
CuO (Cu2+ ) copper (II) Oxide
SnF (Sn4+) tin (IV) fluoride
PbCl (Pb2+) lead (II) chloride
Au2O3 (Au3+) Gold (III) Oxide

17. Ca1 (OH)2 Ca(OH)2 Na2 (CO3) Na2CO3
Polyatomic ions have their own combining capacity that should be used when writing chemical formulas.
Example: Compound formed with Calcium (Ca2+) and Hydroxide (OH-) would be…
Example: Compound formed between Sodium (Na+) and Carbonate (CO32-) would be…
Ca1
(OH)2
Ca(OH)2
USE BRACKETS AROUND THE POLYATOMIC IONS!!
Na2
(CO3)
Na2CO3

18. Naming compounds containing polyatomic ions
Hint: if the fomurla contains more than two elements than it’s a good chance it contains a polyatomic ion, so go to your polyatomic ion chat.
To name these follow the sames rules except for polyatomic ions do not change their names.
e.g. Na3PO4
Sodium Phosphate

19. Covalent Compound Names & Formulas
Prefixes are used before the atom name to indicate the number of atoms in the molecule.
Example:
N3O2 = trinitrogen dioxide
CO = carbon monoxide
trisilicon hexaphosphide
Si3P6
Covalent molecules have subscripts that show the actual number of atoms in the molecule, so DO NOT DIVIDE BY COMMON DENOMINATOR!!