1. Chemical Names and Formulas
Unit 3
Chemical Names and Formulas

2. Homework Read pages 37-39 Finish all of the “atoms” and “ions” WS
Element Name and Symbol WS
Retest Thursday 12/2 or Friday 12/3
Quiz Dec. 6 and 7 (Monday and Tuesday)

3. STABILITY At rest, not willing to react
A state likely to be found in nature
Opposite = reactive or unstable
Stable = 8 valence electrons in outer shell = octet rule
Stability refers to number of ELECTRONS in outer shell

4. Cations Formed by metals Number of outer electrons = group number
Example: Li and Na both have 1 valence electron
How about Mg and Ca?

5. Formation of ions
Sodium has 11 protons and 11 electrons. Sodium loses 1 electron to form a sodium ion

6. ATOM STABILITY
Related to the number of electrons which the atom contains
Atoms will try to lose or gain electrons to achieve a noble gas configuration

7. Noble Gas Rule
Whenever an atom is surrounded by the same number of electrons as a noble gas it is very stable.

8. Anion Formed by non-metals
Gain electrons to achieve noble gas configuration
Charge of the anion = group# - 8
Example: oxide anion has a charge of 6-8 = 2-

9. Formation of ions

10. Anions vs. Cations Anions end in ide Example: bromide, oxide, sulfide
bromide anion = Br1-
oxide anion = O2-
Anion is always larger than the atom from which it was formed

11. sulfur S S2- sulfide bromine Br Br- bromide iron Fe Fe2+ iron(II) aluminum Al Al3+ aluminum calcium Ca Ca2+ calcium lead Pb Pb2+/Pb4+ lead(II) or lead(IV) cesium Cs Cs+ cesium nitrogen N N3- nitride cobalt Co Co2+/Co3+ cobalt(II) or cobalt(III) fluorine F F- fluoride copper Cu Cu+ copper(I) lithium Li Li+ lithium

12. Cation Always smaller than the atom from which it was formed
Metal + ion
Example sodium cation (Na1+)
Magnesium ion (Ca2+)

13. Homework Read pages 40-43 (omit polyatomic ions)
Binary ionic compound worksheet
6.4 Ionic Compound worksheet
Retest Thursday 12/2 or Friday 12/3
Quiz Dec. 6 and 7 (Monday and Tuesday)

14. Compounds Two or more different elements combined chemically
MOLECULAR versus IONIC

15. Ionic Compounds Positive cation + negative anion
Cation gives electrons
Anion accepts electrons
Electrically neutral
Metal + non-metal
Usually solid at room temp.

16. Naming Ionic Compounds
Metal comes first in the name
Non-metal – ending changes to ‘ide’
Example:
NaCl
sodium chloride

17. Chemical Formula
Shows the number and kinds of atoms in the smallest representative unit

18. Formula Unit Lowest whole number ratio of ions in an ionic compound
NaCl NOT Na2Cl2
How is magnesium and chlorine combined to form an ionic compound?

19. Binary Ionic Compounds
Binary – composed of two elements
(+) charge must balance (-) charge
Net charge = 0
Cation is written first

20. Writing Formulas for Binary Ionic Compounds
Potassium Chloride
K+ and Cl-
Charge ratio 1:1
KCl

21. Writing Formulas for Binary Ionic Compounds
Calcium Bromide
Ca+2 and Br-
Charge ratio 2:1
CaBr2

22. Writing Formulas for Binary Ionic Compounds
Use criss cross method
Charge on one ion becomes the subscript on the other
Reduce to lowest whole number ratio.

23. Writing Formulas for Binary Ionic Compounds
Fe3+ combines with O2-
Fe3+ O2- Fe2O3

24. Writing Formulas for Binary ionic Compounds
Ca2+ combines with S2-
Ca2+ S2- Ca2S2
Reduces to CaS

25. Formulas and Names Write formulas from ions Write formulas from names
Ba2+, S2-
Li+, O2-
Ca2+, N3-
Cu2+, I-
Write formulas from names
Sodium iodide
Stannous chloride
Potassium sulfide
Calcium iodide