Download CHEMISTRY NOTES 9.1.1 ATOMS, ELEMENTS, PERIODIC TABLE

CHEMISTRY NOTES 9.1.1
ATOMS, ELEMENTS, PERIODIC TABLE
1. Classify matter according to its atomic structure.
1.1. Review physical and chemical changes of matter using comparisons
1.2. Analyze the relationship and properties of chemical elements taking into account the atomic
and mass numbers; relate to the subatomic particle composition.
1.3. Identify and understand how ions form based on the elemental electron configuration and
locations on the Periodic Table.
1.4. Identify and explain the different types of elements based on the position in the Periodic
Table and the characteristics they express.
MATTER
Matter: any substance that has mass and occupies space; physical material of the universe
Atom: building blocks of matter
Molecule: two or more atoms joined together
Physical states of matter
 Solid: definite shape, definite volume; molecules arranged orderly and close together
 Liquid: definite volume, no specific shape, form shape of container it occupies; molecules
arranged less orderly and are farther apart than solid
 Gas (Vapor): no fixed volume or shape, conforms to the volume and shape of the container it
occupies; molecules are dispersed much farther apart than liquid or solid
Pure substance: matter that has distinct properties and consistent composition (e.g. H 2O, NaCl)
Element: each element is composed of only one type of atom; cannot be decomposed
Relative abundance of elements (percent by mass)
 Universe: @75% hydrogen, @25% helium, <1% other elements
 Earth’s crust: 46.6% oxygen, 27.7% silicon, 8.1% aluminum, 5.0% iron, 3.6% calcium,
2.8% sodium, 2.6% potassium, 2.1% magnesium, 1.5% other elements
 Human body: 65% oxygen, 18.5% carbon, 9.5% hydrogen, 3.2% nitrogen, 1.5% calcium,
1% phosphorus, 0.4% potassium, 0.3% sulfur, 0.2% sodium, 0.2% chlorine, 0.1%
magnesium, <1% other elements
Compound: a substance composed of two or more elements
Law of Constant Composition: elemental composition of a pure compound is always the same
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 e.g. H2O is always 11% hydrogen and 89% oxygen by mass
Mixture:
Combinations of two or more substances in which they retain their own chemical identity
 Heterogeneous: do not have same composition, properties, and appearance throughout (e.g.
rocks, wood)
 Homogeneous (solutions): uniform throughout (e.g. air, salt water)
PROPERTIES OF MATTER
Physical properties:
Can be measured without changing the identity and composition of a substance (e.g. color,
odor, density, melting point, boiling point, hardness)
Chemical properties:
Describes the way a substance may change, or react, to form other substances (e.g.
flammability)
Physical change: changes of state
 Solidification: liquid → solid (hot molten iron left to cool)
 Melting: solid → liquid (e.g. ice melting)
 Evaporation: liquid → gas (water boiling)
 Condensation: gas → liquid (water vapor is cooled and forms into liquid water)
 Deposition: gas → solid (water vapor in sub-zero temperature forms in ice [e.g. snow])
 Sublimation: solid → gas (dry ice [solid CO2] changes to gas form at very low temperatures)
Chemical change (chemical reaction):
A substance is transformed into a chemically different substance
e.g. hydrogen burns in air; hydrogen combines with oxygen to form water
ATOMIC STRUCTURE
Subatomic particles: components of atoms
Some of these components can have a positive or negative charge. Particles with the same
charge repel each other; particles with unlike charges are attracted to one another
 Nucleus: most of the mass of the atom; very little volume occupied
o Proton: positive charge (+)
o Neutron: neutral charge (0)
 Electron cloud: occupies most of the volume of an atom; very little mass of the atom
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o Electron: negative charge (−); located in the space outside the nucleus
Atomic number: number of protons or electrons
Mass number: number of protons plus neutrons
Isotopes: atoms with identical atomic numbers but different mass numbers (neutrons vary)
Isotopes of Carbon
Symbol
11C
12C
13C
14C
Number of Protons
6
6
6
6
Number of Electrons
6
6
6
6
Number of Neutrons
5
6
7
8
Atomic Mass: uses the units amu
Actually the average atomic mass because most elements occur as a mixture of isotopes with
various relative abundances
PERIODIC TABLE
Periodic Table:
Arrangement of elements in order of increasing atomic number, electron configurations, and
chemical properties; 115 known elements
Element information: most periodic table have four pieces of information
 Atomic number: number of protons
 Atomic symbol: symbol used to represent the name of the element
Atomic symbols that don’t match the English name
Element Name
Antimony
Copper
Gold
Iron
Lead
Mercury
Potassium
Silver
Sodium
Tin
Tungsten
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Atomic Symbol
Sb
Cu
Au
Fe
Pb
Hg
K
Ag
Na
Sn
W
Origin
Stibium (Latin)
Cuprum (Latin)
Aurum (Latin)
Ferrum (Latin)
Plumbum (Latin)
Hydrargyrum (Latinized Greek)
Kalium (Neo-Latin)
Argentum (Latin)
Natrium (Latinized Greek)
Stannum (Latin)
Wolfram (German)
Element name
Atomic weight
Periods: horizontal rows; all elements in a period have the same number of electron shells
Groups: vertical columns; often elements in a group have similarities in properties
Metals: 92 of the 115 elements (80%)
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Malleable (can be shaped), fusible (can be fused or melted), ductile (can be formed into wire)
Lose the electrons in their outer shell; form metallic and ionic bonds; transmit heat &
electricity easily because of flow of electrons; form metallic bonds between atoms of the same
element
All metals are solid except Mercury (Hg), which is liquid at room temperature (20°C)
Group 1: Alkali Metals: shiny, soft, highly reactive metals
Group 2: Alkaline Earth Metals: shiny, silvery-white, semi-reactive metals
Groups 3-12: Transition Metals
Form alloys: mixture of two or more elements; main component is metal (e.g. steel is an alloy
of iron and carbon)
Nonmetals: 17 of the 115 elements (15%)
 Volatile (easily vaporized), low elasticity, insulators of heat and electricity; high
electronegativity (tendency to attract electrons)
 At room temperature (20°C) the nonmetals occurs in these states:
o Gases: H, He, N, O, F, Ne, Cl, Ar, Kr, Xe, Ra
o Liquid: Br
o Solid: C, P, S, Se, I
 Diatomic molecules: composed of 2 atoms of the same element
o H2, N2, O2, F2, Cl2, Br2, I2
 Group 17: Halogens: react with metals to produce salts
 Group 18: Noble Gases: odorless, colorless, non-reactive, monatomic gases
o Full electron shells result in low reactivity
Metalloids: 6 of the 115 elements (5%)
 Have a mixture or properties of both metals and nonmetals
 B, Si, Ge, As, Sb, Te
Blocks: a set of adjacent groups; named after the orbital (area that contain electrons)
 s-block: Groups 1 and 2 and He
 p-block: Groups 13-18, not He
 d-block: Groups 3-12 (Transition Metals)
 f-block: Inner Transition Metals
Electron configuration: distribution of electrons of an atom in atomic orbitals
 Useful for understanding the structure of the Periodic Table; describing the chemical bonds
that connect atoms together
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Shell
1
2
3
4
5
Aufbrau Principle: electrons fill the lowest energy orbitals before occupying the higher energy
orbitals
Atomic Orbital: area of the electron subshell where 2 electrons are located
Electron Shell
o Valence shell: the highest (outer) energy shell of an atom; contains the valence
electrons; the electrons that normally will be involved in chemical bonding
Electron Subshells: grouping of atomic orbitals within electron shells
Subshells
1s
2s, 2p
3s, 3p, 3d
4s, 4p, 4d, 4f
5s, 5p, 5d, 5f, 5g
Max e− per Subshell
2
2, 6
2, 6, 10
2, 6, 10, 14
2, 6, 10, 14, 18
Max e− per Shell
2
8
18
32
50
Diagonal Rule: guideline that explains the order in which electrons fill orbitals
Blocks
5
6