Chemistry

1. Bonds
By Regina López and Andrea Herrera

2. What is a bond?
A bond is when two or more atoms are joined
together to reach chemical stability.

3. What are molecules?
A molecule is a combination of two or more atoms.

4. What is a substance?
Substance = matter

5. Pure substances
Elements: Na, C, K, N, Ne.
Compounds: H2O, O2, CH4, C2H6

6. Not Pure Substances
Homogeneous: salt water, gatorade, pepto bismol,
coffee.
Heterogeneous: pozole, Chapala lake, salad, milk and
cereal.

7. What is a compound?
A compound is any substance formed when two or
more elements are bonded.

8. Covalent Bonds
A covalent bond is formed between two nonmetals.
In a covalent bond the electrons are shared.

9. Covalent Bonds
Covalent bonds include diatomic molecules of some
gases.

10. Ion
When an atom gets a charge by either loosing or
gaining electrons.
If it looses electrons it will become a positive ion and
if it gains it will become a negative ion.

11. Ionic Bonds
Ionic bonds are formed between one metal and one
nonmetal.
In ionic bonds there is a gain and loss of
electrons(The metal looses and the nonmetal gains).
Debatable if they are stronger

12. Ionic bonds

13. Polyatomic ions
A polyatomic ion is a bond between two or more
atoms with a charge.
They are formed by a covalent bond and it can make
ionic bonds.

14. Polyatomic ions
In a polyatomic ion the resulting number of electrons
and protons is not equal, an ion with two or more
atoms is formed.

15. Common polyatomic ions

16. Protons
If the atom has more protons than electrons it means
that the atom will become a positive ion.

17. Electrons
If the atom has more electrons than protons it means
that it is a negative ion.

18. Valence electrons
The valence electrons are the electrons in the
outermost layer of the atom.
They determine the element´s behavior.
They are either shared or exchanged.

19. Valence Electrons

20. Valence electrons
Metals usually loose their valence electrons and
nonmetals usually gain them in ionic bonds.

21. Periodic Table
The periodic table has groups and periods.

22. Periods
There are 7 periods and they run horizontally.

23. Groups
There are 8 groups (not counting the middle section
that has weird-acting metals) and they are vertical.
The group number tells you the number of valence
electrons.

24. Reactivity

25. Electronegativity