Transcript Atoms and Elements Notes

Atoms
• Atom- The smallest
particle that can be
called an element.
• All matter is made up
of atoms.
• Made up of
Protons(+), Neutrons,
and Electrons (-)
Elements
• A pure substance
• All atoms of an
element have the
same # of protons.
• An element can not
be broken into
another substance
• No two elements are
the same in their
properties
Element Examples
1.
2.
3.
4.
Element
Hydrogen
Oxygen
Nitrogen
Carbon
Made up of Elements
1. Water
2. Air
3. Rock
Concentrations
The most abundant element in:
The Universe
Hydrogen (H) – 98%
In the Earths Crust
Oxygen- 47%
Silicon- 28%
Three Atomic Particles
1. Proton
a. Found in the Nucleus
b. Positively Charged (+)
c. Is the Atomic #/whole # which = identity
(C=6)
2. Electron
a. Found in a cloud around the Nucleus
b. Negative Charge (-)
c. Same # as the Atomic Number (C = 6)
d. Can be lost or gained to create charged
particles (ions).
e. Determine how elements will bond/react.
3. Neutrons
a. Found in the Nucleus with the
Protons.
b. Neutral/No charge
c. Creates Isotopes which are different
versions of the same element
(i.e.C14 vs. C12)
d. Can be calculated by subtracting the
atomic # from the atomic mass.
Decimal # rounded - Whole # = # of
neutrons
(i.e. C = 12 – 6 = 6 neutrons)
Properties of Matter
1. Physical Property- How a substance
looks, feels, tastes, etc.
Ex. Sugar is white, sweet and granular.
2. Chemical Property- How a substance
reacts to the world round it.
Ex. Sugar will turn to a black solid when
mixed with Sulfuric Acid.
How Matter Changes
Conservation of Mass- Matter is neither created
nor destroyed it just changes form.
1. Physical Change- A change in form that does
not result in a new substance.
Ex. Sugar dissolves in water or any state change.
2. Chemical Change- A change/reaction that
creates a new substance. An indication this is
happening is when you see a color change,
heat, light, smoke/gas and a new byproduct.
Ex. Oxidation (rust), Combustion (burning) or any
Photosynthesis and Cellular Respiration.
Metals
Physical
1. Shininess
2. Conduct Heat and
Electricity
3. High Density (Heavy)
4. Ductile (Can be
made into wire)
5. Malleable (Can be
flattened)
6. All solids except Hg
and H
Chemical
1. Tend to lose
electrons to
make positive
ions.
2. Tend to bond
with non-metals
like oxygen and
water.(Corrosion)
Non Metals
Physical
1. Not Shiny
2. Do not conduct
electricity or heat Chemical
1. Tend to gain
3. Low Density
electrons
to
(lighter)
make negative
4. Brittle (not ductile
ions
or malleable)
5. Can be gas, solid 2. Tend to bond
with metals
or liquid
Alkali Metals
1. First Column
2. Never found alone in
nature because they
are so reactive.
3. React violently with
water due to only
having 1 valence
electron
Halogens
1. Second to last Column
2. Never found alone in nature
3. Highly reactive with Alkali Metals due to 7
electrons in the valence shell
Nobel Gases
1. Last Column
2. Do not react with anything due to having 8
valence electrons
3. All gases
Valence Electrons
• Electrons in the outer most shell
• Can be determined by the column #
(group) that the element exists in.
• All atoms trying to reach the magic 8
number of valence electrons. (Octet Rule)
• Number of valence electrons determines
how reactive an element is and what type
of bonds they form.
Ionic Bonding
• An ion is formed when an
atom gives up an electron
and becomes positive (+)
or an atom gains an
electron an becomes
negative (–)
• An ionic bond is formed
when two opposite
charged atoms come in
contact and stick to
together.
• This the strongest of the
chemical bonds
Covalent Bonding
• Bond created when
two atoms share
electrons
• Not as strong as ionic
bonds (easier formed
and easier broken)
• Carbon makes a lot of
these
Electron Dot Model
1. Determine the # of valence
electrons
2. Draw the atomic symbol
3. Starting at “12 o’clock” place a dot
at 12, 3, 6 and 9
4. If there are more than 4 valence
electrons you then start pairing
electrons at each spot.
5. Bonding sites are all non-paired
electrons