{ Chapter 11 Notes Part 2 Elements and Compounds

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Chapter 11 Notes Part 2

Elements and Compounds

Recall that an atom is the tiniest particle that makes up matter.

All matter is made of atoms

Elements and the Periodic Table

An atom is composed of 3 main particles Protons: Positively charged

particles Electrons: Negatively

charged particles Neutrons: Neutral (no

charge) particles


Protons and Neutrons together make up the nucleus-the center, of the atom.


Matter’s simplest form is the element.

Elements are the building blocks of all matter.

An element is a particle of matter that cannot be broken down into simpler substances.


For example, NaCl is table salt.

You can break down NaCl into Na (Sodium) and Cl (Chlorine)

However, you cannot break down Sodium or Chlorine into simpler substances.

Sodium and Chlorine are elements.Elements and the

Periodic Table

How many atoms are bound together in an element is shown by an elemental formula.


Some elements can exist as single atoms.

For these elements, their formula is the same as their chemical symbol. Examples; Gold (Au), Lithium (Li)

Organization of the Periodic Table

Other elements exist in basic units of two or three atoms.

In these elements, their formula is their chemical symbol followed by a subscript indicating the number of atoms. Examples: Oxygen (O2),

Nitrogen (N2)

Organization of the Periodic Table

There are currently 118 identified elements, 89 of which occur naturally on Earth.


The periodic table is a chart of all known elements arranged in a systematic fashion, represented by their chemical symbols.

It arranges elements with similar chemical properties in the same vertical or horizontal rows.



Vertical rows of elements in the periodic table are called groups or families.

Horizontal rows are called periods or series.



GROUP/FAMILY

SERIES/PERIOD

The periodic table also includes the atomic masses and atomic numbers for each element.


Atomic mass is exactly what it sounds like-the total mass of an atom of that element.


The masses of elements are given in amu-atomic mass units.

1 amu= 1.661 x 10-24 grams 0.000000000000000000000001661 gElements and the

Periodic Table


Atomic number is the number of protons in an atom of that element.


The periodic table is listed in order of increasing atomic number.

We will often identify elements by their atomic number.



The way the periodic table is arranged also tells us a lot about the structure and behavior of different elements.


There are many trends as you move across periods/series or down groups/families.



There are 3 basic groups that make up the periodic table: metals, nonmetals, and metalloids.


Metals are shiny, opaque, and good conductors of both electricity and heat.


Metals are malleable-they can be hammered into different shapes or bent without breaking.


Metals are also ductile- they can be drawn out into wires.


Metals are generally solid at room temperature. Exceptions: Mercury (Hg), Gallium (Ga), Cesium (Cs), and Francium (Fr)



Nonmetals are poor conductors of heat and electricity, and are often transparent.

Nonmetals are brittle, and shatter when hammered.



Metalloids are a small group of elements that have both metallic and nonmetallic properties.

The metalloids are: Boron (B), Silicon (Si), Germanium (Ge), Arsenic (As), Tin (Sn), and Antimony (Sb), and Astatine (At)


Metalloids conduct electricity and heat, but weakly.



When atoms of different elements bond to one another, they make a compound.

Elements to Compounds

H2O

NaCl

NaOH

HCl

There are over 16 million known compounds!


A compound is represented by its chemical formula.

The numbers in the formula represent the ratio of atoms that exist in that compound.


For example, in water (H2O), there are 2 Hydrogen (H) atoms for every 1 Oxygen (O) atom.


Compounds have properties that are different from their elemental components.

Example: NaCl has very different properties from Na and Cl.


There are some basic rules to naming compounds that you will need to know.

Naming Compounds

1. The name of the element farther to the left comes first. The name of the element farther to the right comes second, followed by –ide. Example: Hydrogen and Chlorine.

Hydrogen is further to the left, so it comes first. Chlorine is further to the right, so it

comes second, followed by –ide.

Name: Hydrogen Chloride

Naming Compounds

2. When two or more compounds have different numbers of the same elements, we use prefixes to clarify which one we mean.

Example: Carbon and OxygenCO = Carbon monoxide (mon=one)CO2 = Carbon dioxide (di=two)

Naming Compounds

3. Many compounds are referred to by their “common” name rather than their chemical name.

Examples: Water (H2O), Ammonia (NH3)

Naming Compounds

1. A substance that cannot be broken down into simpler substances is a(n)

A. CompoundB. MixtureC. ElementD. Atom

Review

2. Which of the following would cause a CHEMICAL change?

A. MovingB. ShatteringC. BurningD. Melting

Review

3. Which of the following is a physical change?

A. DissolvingB. EvaporatingC. Bending D. All of the above

Review

4. Which of the following is NOT an example of a physical property?

A. Freezing pointB. ReactivityC. Boiling pointD. Density

Review

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{ Chapter 11 Notes Part 2 Elements and Compounds