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26 Cards in this Set
- Front
- Back
Isotope |
Atoms of the same elements which differ in the number of neutrons (or differ in mass # implying they differ in neutrons)
Diff in neutrons means vary slightly in mass
Therefore relative mass of isotopes is different |
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(Relative) Average Atomic Mass
Of an element |
A number which represents the average weighted mass of all the isotopes of that element |
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Isotopic abundance |
The relative amount in which each isotope is present in an element (see diagram) |
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Radioisotopes |
Radioactive isotopes -nuclei of some atoms unstable -uranium decomposes into polonium and radium -uranium(mass#235) releases radiation and breaks into 2 Lighter atoms *an isotope that spontaneously decays to produce 2 or more smaller nuclei and radiation* |
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Law of Periodicity (periodic law) |
When elements are arranged in order of increasing atomic #, there is a periodic repetition of elements with similar properties
-elements are classified according to sims in chem/phys properties |
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Valence # |
# of electrons which an atom must gain/lose to have outer energy level filled SEE SUMMARY OF ELEMENTS CHART |
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Octet Rule |
Atoms react chemically to achieve a noble (inert) gas electron arrangement |
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KNOW TRENDS |
KNow EM! |
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Ionic bonds |
Form when electrons are completely TRANSFERRED from one atom to another -occur in COMPOUNDS -between metal+non metal atoms -diff in EN is GREATER than 1.7 -non metal PULLS valence e away from metal b/c of EN value -nonmetal-> cation (loses è) -2 + charged ions ATTRACT b/c law of electrostatics |
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Covalent bonds |
Form when electrons are shared between atoms -in molecular compounds -bt 2 Non Metal atoms Diff in EN LESS than 1.7 Both compete valence orbit by attracting valence E from other atom -neither atom strong enough to remove E from other ther for SHARE |
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KNOW PROPERTY CHART |
GO LOOK AT IT |
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2 purposes of IUPAC |
1) provide a nomenclature that would be recognized internationally (UNIVERSAL) so that chemists around the world could efficiently communicate w// 1 another 2) to provide a SYSTEMATIC approach to naming chemicals so that new compounds could easily be named according to existing nomenclature |
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Effective Nuclear Charge |
The net force experienced by an electron in an atom to the positively charged nucleus |
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Type of bonding in ionic compounds is |
IONIC |
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Type of bonding in molecular compounds is |
Covalent (INTRAmolecular) |
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Particles involved in ionic compounds is |
Oppositely charged IONS |
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State @ room temp for ionic compounds |
Crystalline solids |
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State @ room temp for molecular compounds |
Solid, liquid, or gas |
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Melting point for ionic compounds |
High |
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Melting point for molecular compounds is |
Low |
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Ionic compounds Solubility in water is |
High |
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Molecular compound solubility in water is |
Low solubility |
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Ionic compound Electrical conductivity as a liquid? |
Yes! |
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Molecular compound conductivity as a liquid? |
No |
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Electrical conductivity when dissolved in water for ionic compounds? |
Yes! |
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Electrical conductivity when dissolved In water for molecular compounds? |
Not usually... |