1. Chemistry the Essential Element
Atoms elements and their behavior

2. Chemistry Concept Review

3. Atomic Mass V.S. Atomic #
There is a difference between the meanings of atomic mass and mass number. One is the average weight of an element and the other is the total number of nucleons in the atom's nucleus.
Atomic mass is also known as atomic weight. Atomic mass is the weighted average mass of an atom of an element based on the relative natural abundance of that element's isotopes.
Mass number is a count of the total number of protons and neutrons in an atom's nucleus.
Example:
Hydrogen has three natural isotopes: 1H, 2H, and 3H. Each isotope has a different mass number.
1H has 1 proton. Its mass number is 1. 2H has 1 proton and 1 neutron.
Its mass number is 2. 3H has 1 proton and 2 neutrons. Its mass number is 3.
99.98% of all hydrogen is 1H 0.018% of all hydrogen is 2H 0.002% of all hydrogen is 3H Together, they give a value of atomic mass of hydrogen equal to g/mol.

4. How to find # of neutrons?
Remember the formula. To find the number of neutrons in the future, simply use this formula:
# of neutrons =
atomic mass - atomic number

5. How do I find # of protons?
The atomic number is the number of protons in an atom of an element.
Ex: krypton's atomic number is 36. This tells us that an atom of krypton has 36 protons in its nucleus. every atom of krypton contains 36 protons. If an atom doesn't have 36 protons, it can't be an atom of krypton.
Adding or removing protons from the nucleus of an atom creates a different element. For example, removing one proton from an atom of krypton creates an atom of bromine

6. How do I find # of electrons?
By definition, atoms have no overall electrical charge. There must be a balance between the positively charged protons and the negatively charged electrons.
Atoms must have equal numbers of protons and electrons. An atom of krypton must contain 36 electrons since it contains 36 protons.

7. What is an ion?
Ion-An atom or molecule with a net electric charge due to the loss or gain of one or more electrons.
An atom can gain or lose electrons, becoming what is known as an ion. An ion is nothing more than an electrically charged atom. Adding or removing electrons from an atom does not change which element it is, just its net charge.
For example, removing an electron from an atom of krypton forms a krypton ion, which is usually written as Kr+. It is positively charged because a negatively charged electron was removed from the atom.
The plus sign means that this is a positively charged ion. The 35 remaining electrons were outnumbered by the 36 positively charged protons, resulting in a charge of +1.

8. Neutral, Negative, Positive

9. In Summary For any element: Number of Protons = Atomic Number
Number of Electrons = Number of Protons = Atomic Number
Number of Neutrons = Mass Number - Atomic Number
For krypton:
Number of Protons = Atomic Number = 36
Number of Electrons = Number of Protons = Atomic Number = 36
Number of Neutrons =
Mass Number - Atomic Number = = 48

10. Mixture v.s. Compound:
What is the difference?

11. Mixtures Mixtures are impure substances.
They are made up of two or more substances mixed physically.
The constituents of a mixture are present in varying ratios.
Mixtures do not have fixed properties. Their properties depend on the nature of their components and the ratios in which they are combined.
In mixtures, no new substance is formed. The properties of a mixture are the same as the properties of its constituents.
The constituents of a mixture can be separated easily by physical methods.
DO NOT WRITE THIS DOWN

12. Mixtures 2
Individual molecules or parts not chemically reacting with each other
When you see distilled water (H2O), it's a pure substance. That means that there are only water molecules in the liquid.
Individual molecules enjoy being near each other, but their fundamental chemical structure does not change when they enter the mixture. If the chemical structure changed, it would be called a reaction.  When you see distilled water (H2O), it's a pure substance. That means that there are only water molecules in the liquid. A mixture would be a glass of water with other things dissolved inside, maybe one of those powders you take if you get sick. Each of the substances in that glass keeps its own chemical properties. So, if you have some dissolved substances in water, you can boil off the water and still have those dissolved substances left over. If you have some salt (NaCl) in water and then boil off the water, the salt remains in the pan. The salt is left because it takes very high temperatures to melt salt (even more to boil it). Which is a mixture and why?

13. Mixtures 3
Solutions are also mixtures, but all of the molecules are evenly spread out through the system. They are called homogenous mixtures.
A heterogeneous mixture does not have a definite composition. Although you may add one substance to the other, they will stay separate in the mixture. We say that these heterogeneous mixtures are non-uniform,
in other words they are not exactly the same throughout.
Salt and water is an example of a solution
Heterogeneous mixture ex: Cereal in milk is an example of a heterogeneous mixture. Soil is another example. Soil has pebbles, plant matter and sand in it.

14. Mixture Types
Homo= same Hetero= different

15. Watch video on how to make a distiller
How a water treatment plant works

16. Mixtures Pt 4: Alloys
Alloys are basically a mixture of two or more metals. Don't forget that there are many elements on the periodic table. Elements like calcium (Ca) and potassium (K) are considered metals. Of course, there are also metals like silver (Ag) and gold (Au). You can also have alloys that include small amounts of non-metallic elements like carbon (C). Metals are the key thing to remember for alloys.
The combinations of metals work better together than any of the metals do alone. Metallurgists (people who work with metals) sometimes add chromium (Cr) and/or nickel
(Ni) to steel. While steel is already an alloy that is a very strong metal, the addition of small amounts of the other metals help steel resist rusting
. Depending on what element is added, you could create Stainless Steel or Galvanized Steel. It's always about improving specific qualities of the original. Another good example of an alloy happens when metallurgists add carbon to steel. A tiny amount of carbon (a non-metallic element) makes steel stronger. These special carbon-steel alloys are used in armor plating and weapons.
What two elements are steel made of?
What elements are added to make Stainless or Galvanized Steel?
What is the Carbon/Steel Alloy called?

17. Compounds
Compounds are groups of two or more elements that are bonded together.
Molecule is the general term used to describe atoms connected by chemical bonds. Every combination of atoms is a molecule. Compounds happen with atoms from different elements.
Not all molecules are compounds because sometimes the atoms are of the same element. Hydrogen gas (H2) is a good example of a molecule that is not a compound. 
So, all compounds are molecules, because they have bonds between the atoms, like in water (H2O).

18. Characteristics of Compounds
Compounds are pure substances.
They are made up of two or more elements combined chemically.
The constituents of a compound are present in a fixed ratio.
Compounds have fixed properties.
A compound can have properties different from its elements, as a new substance is formed when the elements are chemically combined.
The elements of a compound can be separated only by chemical methods.
Compounds have fixed properties. For example, a particular compound will have fixed temperatures at which it melts and boils.

19. Hydrogen Element and Water Molecule
Hydrogen molecules usually like to stick together in pairs. They both only have one electron and they want a full electron shell so they share electrons with each other when they bond.
Hydrogen molecules are seeking an extra electron and oxygen is looking to add two more to its outer shell.

20. Ionic Bonds
An ionic bond is a type of chemical bond formed through an attraction between two oppositely charged ions.
Ionic bonds are formed due to the attraction between an atom that has lost one or more electron (known as a cation) and an atom that has gained one or more electrons (known as an anion).
Usually, the cation is a metal atom and the anion is a nonmetal atom.

21. Common table salt is sodium chloride
Common table salt is sodium chloride. When sodium (Na) and chlorine (Cl) are combined, the sodium atoms each lose an electron, forming cations (Na+)
The chlorine atoms each gain an electron to form anions (Cl−). Na + Cl → Na+ + Cl− → NaCl
These ions are then attracted to each other in a 1:1 ratio to form sodium chloride (NaCl).

22. Ionic Bond Visual
Na gives the extra electron to Cl

23. Ionic Bonds Cont.
Na has an extra electron on its outter shell that it wants to give away. When it comes into contact with Cl that is missing an electron on its outter shell it gives its electron to CL. Na was neutrally charged but is now positively charged after giving away one of its electrons. CL was neutrally charged but is now negatively charged after gaining the electron it was looking for.

24. Difference Between Covalent and Ionic Bond

25. Ionic Bond Animation
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26. Covalent Bonds
Covalent Bonds: a chemical bond that involves sharing a pair of electrons between atoms in a molecule.

27. Covalent Bonds

28. Covalent Bonds

29. Covalent Bonds

30. Covalent Bonds
Covalent Bond Animation

31. Covalent vs. Ionic
Simple explanation of Covalent v.s. Ionic
Detailed/ Long Video about Ionic and Covalent Bonds and polarity

32. Mixture, Elements, Compounds
Chemically
Separable ?

33. Chemical Reactions: Explosive Possibilities

34. Chemical Reactions
Funny animation

35. Balancing Chemical Equations