- 1.
- Elements and the Periodic Table
2.
- Classification is arranging items into groups or categories
according to some criteria.
- The act of classifying creates a pattern that helps you
recognize and understand the behavior of fish, chemicals, or any
matter in your surroundings.
3.
4.
- Matteris usually defined as anything that has mass and occupies
space.
5. GasLiquidSolid Total disorder Lots of empty space Disorder
Some space Particles closer together Order Particles fixedin
position 6.
- Solids, Liquids, and Gases
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- Gaseshave no defined shape or defined volume
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- Liquidsflow and can be poured from one container to
another
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- Indefinite shape and takes on the shape of the container.
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- Solidshave a definite volume
7.
- Mixtures and Pure Substances
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- Amixture has unlike parts and a composition that varies from
sample to sample
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- Aheterogeneous mixturehas physically distinct parts with
different properties.
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- Ahomogeneous mixtureis the same throughout the sample
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- Pure substancesare substances with a fixed composition
8.
- A classification scheme for matter.
9.
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- Aphysical changeis a change that does not alter the identity of
the matter.
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- Achemical changeis a change that does alter the identity of the
matter.
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- Acompoundis a pure substance that can be decomposed by a
chemical change into simpler substances with a fixed mass
ratio
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- Anelementis a pure substance which cannot be broken down into
anything simpler by either physical or chemical means.
10.
- Sugar (A) is a compound that can be easily decomposed to
simpler substances by heating. (B) One of the simpler substances is
the black element carbon, which cannot be further decomposed by
chemical or physical means.
11.
- pure substanceandcompound
EXAMPLE E 12.
13.
- Reconsidering the Fire Element
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- Thephlogiston theoryviewed phlogiston as a component of all
matter.
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- The burning of a material was considered to be the escaping of
phlogiston from the matter.
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- If a material did not burn, it was considered to contain no
phlogiston.
14.
- The phlogiston theory. (A) In this theory, burning was
considered to be the escape of phlogiston into the air. (B)
Smelting combined phlogiston-poor ore with phlogiston from a fire
to make a metal. (C) Metal rusting was considered to be the slow
escape of phlogiston from a metal into the air.
15.
- Discovery of Modern Elements
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- Antoine Lavoisier suggested that burning was actually a
chemical combination with oxygen.
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- Lavoisier realized that there needed to be a new concept of
elements, compounds, and chemical change.
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- We now know that there are 89 naturally-occurring elements and
at least 23 short-lived and artificially prepared.
16.
- Priestley produced a gas (oxygen) by using sunlight to heat
mercuric oxide kept in a closed container. The oxygen forced some
of the mercury out of the jar as it was produced, increasing the
volume about five times.
17.
- Lavoisier heated a measured amount of mercury to form the red
oxide of mercury. He measured the amount of oxygen removed from the
jar and the amount of red oxide formed. When the reaction was
reversed, he found the original amounts of mercury and oxygen.
18.
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- The first 103 elements have internationally accepted names,
which are derived from:
-
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- The compound or substance in which the element was
discovered
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- An unusual or identifying property of the element
-
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- Places, cities, and countries
19.
- Here are some of the symbols Dalton used for atoms of elements
and molecules of compounds. He probably used a circle for each
because, like the ancient Greeks, he thought of atoms as tiny,
round hard spheres.
20.
- The elements of aluminum, Iron, Oxygen, and Silicon make up
about 88 percent of the earth's solid surface. Water on the surface
and in the air as clouds and fog is made up of hydrogen and oxygen.
The air is 99 percent nitrogen and oxygen. Hydrogen, oxygen, and
carbon make up 97 percent of a person. Thus almost everything you
see in this picture us made up of just six elements.
21. Atomic theory 22. Daltons Postulates
- Every element is composed of tiny particles called atoms
- All atoms of a given element are identical
-
- Atoms of different elements have different properties
- Atoms of an element are NOT changed into atoms of another
element by chemical processes
-
- Matter can neither be created nor destroyed
- Compounds are formed when atoms of more than one element
combine
23. Daltons Laws
- The Law of Constant Composition:
- Any given compound always consists of the sameatoms and the
same ratio of atoms. For example, wateralways consists of oxygen
and hydrogen atoms, andit is always 89 percent oxygen by mass and
11 percenthydrogen by mass
- 2. The Law of Conservation of Mass:
- The total mass of materials before and after a chemical
- reaction must be the same. For example, if we combine
- 89 grams of oxygen with 11 grams of hydrogen under
- the appropriate conditions, 100 grams of water will be
- producedno more and no less.
24. Daltons Laws 3. The Law of Multiple Proportions: If two
elements combine to form more than one compound, the masses of one
of the elements that can combine with a givenmass of the other
element are related by factors of small whole numbers For example,
water has an oxygen-to-hydrogen mass ratio of 7.9:1.Hydrogen
peroxide, another compound consisting of oxygen andhydrogen, has an
oxygen-to-hydrogen mass ratio of 15.8:1.The ratio of these two
ratios gives a small whole number. 25. MODERN ATOMIC THEORY 26.
-
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- There are about a dozen common elements that have s single
capitalized letter for their symbol
-
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- The rest, that have permanent names have two letters.
-
-
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- the first is capitalized and the second is lower case.
-
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- Some elements have symbols from their Latin names.
-
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- Ten of the elements have symbols from their Latin or German
names.
27.
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- Symbols and Atomic Structure
-
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- Amoleculeis a particle that is composed of two or more atoms
held together by a chemical bond.
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- Isotopesare atoms of an element with identical chemical
properties, but different masses due to a difference in the number
of neutrons.
-
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- Theatomic massof an element is the average of all the atomic
masses of the isotopes.
-
-
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- an isotopes contribution is determined by its relative
abundance.
28.
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- The mass of an element is the mass of the element compared to
an isotope of carbon Carbon 12.
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-
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- Carbon 12 is assigned an atomic mass of 12.00 g.
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-
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- 12.00 is one atomic mass unit
-
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- The number of protons and neutrons in an atom is itsmass number
.
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- Atomic numbers are whole numbers
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- Mass numbers are whole numbers
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- The atomic mass is not a whole number.
29. Symbol Atomic Mass Atomic Number Charge(if ion) 30. H
Hydrogen 1 1 Protons: 1 Neutrons: 0 Electrons: 1 31. Na Sodium 23
11 Protons: 11 Neutrons: 12 Electrons: 11 32. Rhenium Re 186 75
Protons: 75 Neutrons: 111 Electrons: 75 33. Rhenium isotope Re 187
75 Protons: 75 Neutrons: 112 Electrons: 75 34. EXAMPLE How many
protons, neutrons and electrons are found in anatom of Cs Atomic
number = protons and electrons There are 55 protons and 55
electrons Mass number = sum of protons and neutrons 133 55 = 78
There are 78 neutrons 133 55 35.
36.
- Dmitri Medeleevgave us a functional scheme with which to
classify elements.
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- Mendeleevs scheme was based on chemical properties of the
elements.
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- It was noticed that the chemical properties of elements
increased in a periodic manner.
-
- The periodicity of the elements was demonstrated by Medeleev
when he used the table to predict to occurrence and chemical
properties of elements which had not yet been discovered.
37.
- Mendeleev left blank spaces in his table when the properties of
the elements above and below did not seem to match. The existence
of unknown elements was predicted by Mendeleev on the basis of the
blank spaces. When the unknown elements were discovered, it was
found that Mendeleev had closely predicted the properties of the
elements as well as their discovery.
38.
-
- Similar physical and chemical properties recur periodically
when the elements are listed in order of increasing atomic
number.
39.
- The Modern Periodic Table
40.
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- The periodic table is made up of rows of elements and
columns.
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- An element is identified by its chemical symbol.
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- The number above the symbol is the atomic number
-
- The number below the symbol is the rounded atomic weight of the
element.
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- A column is called agroup
41.
- (A) Periods of the periodic table, and (B) groups of the
periodic table.
42.
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- The chemical behavior of elements is determined by its electron
configuration
-
- Energy levels are quantized so roughly correspond to layers of
electrons around the nucleus.
-
- A shell is all the electrons with the same value of n.
-
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- n is a row in the periodic table.
-
- Each period begins with a new outer electron shell
43.
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- Each period ends with a completely filled outer shell that has
the maximum number of electrons for that shell.
-
- The number identifying the A families identifies the number of
electrons in the outer shell, except helium
-
- The outer shell electrons are responsible for chemical
reactions.
-
- Group A elements are calledrepresentative elements
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- Group B elements are calledtransition elements .
44.
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- IA are calledalkali metalsbecause the react with water to from
an alkaline solution
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- Group IIA are called thealkali earth metalsbecause they are
reactive, but not as reactive as Group IA.
-
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- They are also soft metals like Earth.
-
- Group VIIA are thehalogens
-
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- These need only one electron to fill their outer shell
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- Group VIIIA are thenoble gasesas they have completely filled
outer shells
-
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- They are almost non reactive.
45.
- Four chemical families of the periodic table: the alkali metals
(IA), the alkaline earth metals (IIA), halogens (VII), and the
noble gases (VIIIA).
46. Metal:Elements that are usually solids at room
temperature.Most elements are metals. Non-Metal:Elements in the
upper right corner of the periodicTable.Their chemical and physical
properties are different from metals. Metalloid:Elements that lie
on a diagonal line between theMetals and non-metals.Their chemical
and physical properties are intermediate between the two. 47.
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- When an atom or molecule gain or loses an electron it becomes
an ion.
-
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- Acationhas lost an electron and therefore has a positive
charge
-
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- Ananionhas gained an electron and therefore has a negative
charge.
48.
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- Elements with 1, 2, or 3 electrons in their outer shell tend
toloseelectrons to fill their outer shell and become cations.
-
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- These are themetalswhich always tend to lose electrons.
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- Elements with 5 to 7 electrons in their outer shell tend
togainelectrons to fill their outer shell and become anions.
-
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- These are thenonmetalswhich always tend to gain electrons.
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- Semiconductors(metalloids) occur at the dividing line between
metals and nonmetals.
49. What would the charge be on a sodium ion? EXAMPLE Since
sodium in in Group IA it is a metal and so would LOSEan electron
You can tell how many would be lost by the group number Group 1A
elements lose 1 electron So the charge would be +1 Remember an
electron is negatively charged.When you losethem atom becomes
positively charged when you gain them it becomes negatively charged
50. How would you right the symbol for the sodium CATION? EXAMPLE
Na +1 How many outer electrons does sodium have before itloses one?
It has 1remember the group number!