1. Chemical compounds

2. Learning goals We are learning about chemical compounds.
We are learning to identify parts of chemical formulas.
We are learning to identify two types of chemical compounds.

3. Chemical compounds Formed from elements in periodic table
Formed from 2 or more elements
We use them in every day life!

4. Chemical compounds Have an official name and a chemical name
Can be identified by words and symbols

5. reactivity
The closer to an atom is to a full outer electron shell, the more reactive it is
How likely an atom will take part in a chemical reaction and form a compound
The atoms of group 18 are not reactive at all
Noble gases
Full outer electron shell

6. Try this Name the least reactive group of elements. Why?
Nobel gases! Full outer shell!
Name the two most reactive. Why?
Alkali (grp 1) and Halogens (grp 17). One electron away from noble gas!
Name the element in each pair that is more reactive:
Na and Mg
S and Cl
K and Na
F and Cl

7. Chemical formulas
A group of letters and subscript numbers that represent the make-up of a chemical compound
H2O
symbol for element hydrogen
symbol for element oxygen
No small number here means 1 atom of oxygen
Small number here means 2 atoms of hydrogen

8. Try this
CaCO3
Na3PO4
MgCl2
NaC5H8NO4
H2O2
C6H12O6
CO2
CCl2F2
CH2F2

9. Please complete
What does the subscript in a chemical formula tell you?
What does no subscript mean?
For the compound ammonia, NH4, how many nitrogen atoms are there, and how many hydrogen atoms are there in each molecule?
Write a chemical formula for a compound that is made of one atom of carbon (C) and 4 atoms of hydrogen (H)?
Write the chemical formula for a compound that has two atoms of nitrogen and four atoms of oxygen.

10. stability When elements form compounds, they become more stable.
All elements try to achieve a full, stable outer electron shell that noble gases have.

11. stability Elements achieve a full shell in one of three ways:
Metals lose electrons to form positive ions.
Non-metals gain electrons to form negative ions.
Non-metals share electrons.

12. ions An atom or group of atoms that has an electrical charge.
Can be either positive or negative.

13. Types of compounds
Two types:
Ionic
Molecular

14. Ionic compounds Metal ions are positively charged
Non metal ions are negatively charged
Ionic compounds form because metal ions and non-metal ions are attracted to each other.

15. Ionic properties Solid at room temperature Very high melting points
Conduct electricity when melted or dissolved in water

16. Molecular compounds
Non-metal atoms can share electrons with other non-metal atoms
Hydrogen is included here

17. Molecular properties Solids, liquids, or gases at room temperature
Lower melting points than ionic compounds
Do not conduct electricity when melted or dissolved in water

18. Ionic or molecular NaCl CH4 CO CaCl2 C12H22O11 CCl4 CaO MgO CuBr2
CH3OH

19. Learning goals We are learning about chemical compounds.
We are learning to identify parts of chemical formulas.
We are learning to identify two types of chemical compounds.