1. Combination of elements to form compounds
Benchmark SC.8.P.8.5  Recognize that there are a finite number of elements and that their atoms combine in a multitude of ways to produce compounds that make up all of the living and non-living things that we encounter

2. Elements chemically combined?
Compounds
A compound is a substance which is made up of two or more elements that have been chemically combined together.
Elements chemically combined?
What do you mean?

3. Sodium- is a soft silvery white metal that reacts violently with water
Compounds
Sodium- is a soft silvery white metal that reacts violently with water
Chlorine-is a poisonous, greenish yellow gas. +
It is different to Sodium and different to Chlorine!
Table salt is made out Sodium and Chlorine.
Cannot be separated by physical means!
Put the two together = sodium chloride!! Table Salt, a perfectly safe, edible compound
NaCl
Sodium chloride
(table salt)

4. A compound… Let’s check!
Is a substance which is made up of two or more elements that have been chemically combined.
Can be broken down into a simpler type of matter (elements) by chemical means (but not by physical means).
Has properties that are different from its component elements. Ex: In a water molecule Hydrogen and Oxygen are gases but when they combine together they form a liquid.
Always contains the same ratio of its component atoms. Ex: In a water molecule there are 2 Hydrogen atoms per every Oxygen atom (H2O). And in a peroxide molecule there are 2 Hydrogen atoms per every 2 Oxygen atoms.

5. Yes! What is a compound? Why not? Why not? Why not?
A compound is a substance which is made up of two or more elements that have been chemically combined together.
Is this a compound?
Is this a compound?
Is this a compound?
Is this a compound? H O O H
It only contains one type of element. Cu
It only contains one type of element. H H
It is not chemically combined. O H O H
Yes!
Why not?
Why not?
Why not?

6. Examples of compounds ACIDS BASES taste sour
and turn blue litmus paper red.
BASES
feels slippery
and turns blue litmus paper darker blue.

7. Types of Substances Created from the Periodic Table
Compounds (2+ Elements)
2 or more elements that have combined chemically. (bonded)
Can have different properties than the elements that make them up.
Example – water
Water is different than the elements hydrogen and oxygen.

8. Types of Substances Created from the Periodic Table
Mixtures (Heterogeneous)
Combination of 2 or more substances that have NOT combined chemically.
Substances can be easily separated and still have their own identities.
Example: A supreme pizza. Every piece has a different ratio of toppings. I can pick them of and each piece is its own entity.

9. Types of Substances Created from the Periodic Table
Solutions (homogeneous)
Combination of 2 or more substances that have NOT been combined chemically
The solution has the same properties throughout.
Example: Bronze is a solution. In order to be created a specific ratio of copper and tin must be mixed together. If you look at a piece of bronze, you cannot tell that there are two different elements present.

10. Produce H+ (as H3O+) ions in water Tastes sour. REACTS with metals
ACIDS
Produce H+ (as H3O+) ions in water
Tastes sour.
REACTS with metals
React with bases to form salts and water
BASES
Produce OH- ions in water
Taste bitter, chalky
Feel soapy, slippery
React with acids to form salts and water

11. Atoms! The Legos of the Universe

12. Atom: the smallest unit of matter, a nucleus surrounded by an electron cloud.
“atom” is from the Greek word “atomos” which means
“not able to be divided.”
The Atom

13. All atoms are made of the same 3 subatomic (smaller than an atom) particles.
Inside the atom

14. Inside the atom…

15. Inside the nucleus of an atom

16. Inside the nucleus of an atom

17. If there are both protons and neutrons in the nucleus, why does the nucleus have a positive charge?
Protons are positive, and neutrons are neutral, so they don’t give any charge!
Key Questions

18. Outside the nucleus…

19. -
Electron
Nucleus +
Neutron
The Atom
Proton
Electron Cloud

20. What units do you use to measure the mass of an atom?
 Atomic Mass Units (AMU)
Atomic Mass Units (AMU)
 1 AMU = Mass of one proton  1 AMU = Mass of one neutron
How Do You Weigh an Atom?

21. Sizes of Subatomic Particles
How big are protons, electrons, and neutrons compared to each other?
Big
Tiny + -
Sizes of Subatomic Particles

22. Summary of Key Concepts
Particle
Charge
Mass (AMU)
Location
Proton + 1
Nucleus
Electron -
1/1830 ≈ 0
Electron Cloud
Neutron Ѳ
Summary of Key Concepts

23. Summary of Key Concepts
Protons (+) = Electrons (-)
#Neutrons =
Atomic Mass – Atomic Number
Atomic Mass =
# Protons + # Neutrons
Summary of Key Concepts

24. Formative Checkpoint (Fill in this table)
Does it Have CELLS?
Does it have ATOMS?
Living Things
Non-Living Things

26. Elements
The elements, alone or in combinations, make up our bodies, our world, our sun, and in fact, the entire universe.

27. Key to the Periodic Table
Elements are organized on the table according to their atomic number, usually found near the top of the square.
The atomic number refers to how many protons an atom of that element has.
For instance, hydrogen has 1 proton, so it’s atomic number is 1.
The atomic number is unique to that element. No two elements have the same atomic number.

28. What’s in a square?
Different periodic tables can include various bits of information, but usually:
atomic number
symbol
atomic mass
number of valence electrons
state of matter at room temperature.

29. Atomic Number
This refers to how many protons an atom of that element has.
No two elements have the same number of protons.
Bohr Model of Hydrogen Atom
Wave Model

30. Atomic Mass Atomic Mass refers to the “mass” of the atom.
It is derived at by adding the number of protons with the number of neutrons.
This is a helium atom. Its atomic mass is 4 (protons plus neutrons).
What is its atomic number? H

32. ADD a Proton from left to right

33. Families Periods Columns of elements are called groups or families.
Elements in each family have similar but not identical properties.
For example, lithium (Li), sodium (Na), potassium (K), and other members of family IA are all soft, white, shiny metals.
All elements in a family have the same number of valence electrons.
Each horizontal row of elements is called a period.
The elements in a period are not alike in properties.
In fact, the properties change greatly across even given row.
The first element in a period is always an extremely active solid. The last element in a period, is always an inactive gas.
Families Periods

34. Families(Groups)

45. Hydrogen
The hydrogen square sits atop Family AI, but it is not a member of that family. Hydrogen is in a class of its own.
It’s a gas at room temperature.
It has one proton and one electron in its one and only energy level.
Hydrogen only needs 2 electrons to fill up its valence shell.

46. Alkali Metals
The alkali family is found in the first column of the periodic table.
Atoms of the alkali metals have a single electron in their outermost level, in other words, 1 valence electron.
They are shiny, have the consistency of clay, and are easily cut with a knife.

47. Alkali Metals They are the most reactive metals.
They react violently with water.
Alkali metals are never found as free elements in nature. They are always bonded with another element.

48. All matter is composed of atoms and groups of atoms bonded together, called molecules.
Substances that are made from one type of atom only are called pure substances.
Substances that are made from more than one type of atom bonded together are called compounds.
Compounds that are combined physically, but not chemically, are called mixtures.
Matter

49. Elements, Compounds, Mixtures
Sodium is an element.
Chlorine is an element.
When sodium and chlorine bond they make the compound sodium chloride, commonly known as table salt.
Compounds have different properties than the elements that make them up.
Table salt has different properties than sodium, an explosive metal, and chlorine, a poisonous gas.

50. Elements, Compounds, Mixtures
Hydrogen is an element.
Oxygen is an element.
When hydrogen and oxygen bond they make the compound water.
When salt and water are combined, a mixture is created. Compounds in mixtures retain their individual properties.
The ocean is a mixture.

51. Elements, compounds, and mixtures
Mixtures can be separated by physical means.
Compounds can only be separated by chemical means.
Elements are pure substances. When the subatomic particles of an element are separated from its atom, it no longer retains the properties of that element.
Elements, compounds, and mixtures