Chem trends Flashcards
Scientists:
Lavoisier: got lists
Newlands: organized by atomic mass
Mendeleev: gets credit, made predictions.
Moseley: arranged by atomic number
Periodic Law
when elements are in increasing atomic #, they are w/ similar properties at regular intervals.
Periodicity
patterns in groups (vertical) and periods (horizontal)
atomic radius
Metallic
half the distance of nuclei.
increases to LEFT and BOTTOM
- ionization energy: energy required to remove 1 electron from neutral atom. increases at
- electron affinity: e- is gained
- electronegativity: measure of ability to attract electrons
increases TOP and RIGHT
ionic radius
distance from center to outer e- increases at BOTTOM and right
Metallic bonds
attractions of cation to delocalized electrons, good conductors
metals, ionic
shiny, malleable/ductile, high melting points.
covalent
weak bond, low melting point
nonpolar covalent
e- shared equally
polar
e- shared unequally, diff in electronegativity
Lewis structures
- H always outside
- C always center
bond energy
energy required to break a bond. strongest= shortest and triple. 2,4,6
exceptions to octet rule
- Boron likes to have 6
- s,p,br,i,xe have more than 8
vsepr thoery
used to predict molecular geometry of covalent. repulsion of valence
hybridization
mixing atomic orbitals. group 15&16
linear; sp
trignomial planar; sp2
tetrahedral; sp3
metals
left, not hydrogen. valence 1 and 2. solid, shiny, good conductors, malleable and ductile. reactivity increases down left
nonmetals
top right and hydroge. 4, 5, 6, 7,8. dull brittle poor conductors not malleable. reactivity increases up and right
transitional metals
high melting points, covalent, good conductors, hard to bent/hammers
alkali metals
group 1,soft, silvery, low boiling point. found naturally in nature. very reactive w/ water
alkaline earth metal
soft silver,
halogens
group 17, toxic, nonpolar covalent. most reactive in nonmetal.
Lanthanide and Actinides
L: abundant, tarnish, dissolve. reacts w/ halogens
A:rare earth metals, man made, radioactive, toxic, nuclear energy
Noble gases
group 18, non reactive. low boiling point. oderless and colorless. extremely rare
Hydrogen/Helium
Helium:2nd abundant, raises pitch of voice, 2nd least reactive. low boiling point, lighter than air (balloon)
Hydrogen: most abundant, light, reactive. becomes Helium
Boron family
group 13, metallic, silvery white nonmetal except for boron
carbon family
group 14 carbon is a non-metal, silicon and germanium are metalloids, and tin and lead are poor metals.
Nitrogen family
group 15. melting point increse down the group
oxygen family, chalogen
ch. 16 found in pure form in nature
