Chem. Exam 1 Flashcards
Nuclide is characterized by
protons or atomic #
# neutrons
mass # (#p + #n)
Isotopes
Nuclides of same elements w/ same diff. # neutrons (or diff. mass #s)
Isotopes of Hydrogen & they’re components
Protium (1 p & 0 n) (99.985 %)
Deuterium (1 p & 1 n) (0.015%)
Tritium (1 p & 2 n) (radioactive)
Isotopes of Carbon & they’re components
C12: (6 p & 6 n) (98.89%)
C13: (6 p & 7 n) (1.11%)
C14: (6 p & 8 n) (radioactive)
Chemical Formula
Diff. atoms combine to form compounds where subscripts indicate relative # of atoms present
Chemical Bonds
How atoms are connected together but vary from compound to compound
Covalent Bonding
sharing of e- to hold atoms in molecules together
Ionic Bonding
e- are completely transferred from on atom to another
- usually involves metal and nonmetal
- attraction between cation (+) & anion (-)
- results in formation of ions
Ion
charged atom
Non-directional bond & ex.
Ionic: has interactions w/ many diff. ions resulting in ionic solid (ex. salt)
Isotropic
finds anything around them that isn’t oppositely charged
Modern Periodic Table vs Mendeleev
Modern: links together families of elements that have similar chemical or physical composition
Mendeleev: based on atomic masses of elements
Eight Groups of Main Group Elements
- Alkali Metals
- Alkaline Earth Metals
- Boron family (teriels)
- Carbon family (tetrels)
- Nitrogen group (pnictogens)
- Chalcogens
- halogens
- Noble gases
part of atom that determines its chemistry
e- in an atom
Actinides
most produced artificially (except uranium and thorium have reasonable natural occurrence)
Core e-
Aren’t usually available for bonding (exception is group 1B) (Ag, Cu, & Au may have valences of 1,2, or 3)
Characteristics of Metals
Malleable (hammered into sheet)
Ductile (drawn into wire)
Luster (shinyness)
Good conductor of heat & electricity
Characteristics of Non-Metals
Brittle
Dull color
Bad conductor of heat & electricity
Semimetals/Metalloids
have characteristics that resemble metals in some regards and nonmetals in others
Sides of periodic table & which is metallic
Left: metalic
Right: nonmetalic
Hydrogen facts
- most abundant element on earth
- flammable
- lighter than oxygen so it floats
Helium facts
- 2nd most abundant element
- non-flammable
- lighter than oxygen so it floats
- used in cytogenetics & MRI
Alkali Metal (what happens when it combines w/ water?; are they soft or hard?; are they malleable & ductile?; are they reactive toward water?)
- combines with water to form alkaline solutions
- soft (can be cut w/ a knife)
- malleable & ductile (ex. sodium wire)
- HIGHLY reactive towards water
Alkali Earth Metals (hardness & reactivity)
- harder the alkali metals
- less reactive then alkali metals
Meaning of EARTH is alkali earth metals
substances that are insoluble in water & stable to heat (oxides of these elements)
Magnesium reactivity w/ water vs steam vs burning in CO2
Water: slow
Steam: quickly to form magnesium hydroxide
CO2: creates magnesium oxide & carbon
How fire extinguishers work
displace oxygen (feeds fire) with CO2
Most toxic element
Tl
Boron group
- transition from semimetallic to metalic
- all form TRIVALENT compound 1:3 EXCEPT (idiom & thallium which form monovalent compounds 1:1) (inert pair effect)
Inert Pain effect
Reluctance of valence electrons to participate in bonding
- lone pair becomes more stable for heavy elements
