Chem Ch 6

name of Group 1A metals

alkali metals-not H

Group 1A metals properties

react with air-stored in oil

name of Group 2A metals

alkaline-earth metals

Group 2 metals characteristics

denser than H2O

where are metalloids located?

above staircase and below except Al and Po

decreasing metal reactivity

across period

increasing metal reactivity

down group

halogens

group 17, to the left of noble gases

metals characteristics

good conductors of heat/electricity, typically solids at room temp, malleable, ductile, luster

nonmetals characterisitcs

poor conductors of heat/electricity, solids, liquids and gases at room temp, solids are brittle and dull

metalloids characteristics

properties of metals and nonmetals, mostly brittle solids, semiconductors

alkali metals properties

extremely reactive-reacts with water violently to form H2 gas and alkali solutions, reacts with oxygen in air, silvery, can be cut with knife, lower densities and melting points than other metals, no free elements found in nature

alkaline-earth metals properties

harder, stronger, less reactive, higher densities and melting points than alkali metals, no free elements found in nature

halogens properties

most reactive nonmetals, react readily with most metals to form salts, most electronegative elements

Coulombic attraction

attraction between oppositely charged particles

why does K have a larger atomic radius than H?

H has 1 energy lvl so its valence e- is really close to nucleus; K has more energy lvls pushing its valence e- a lot farther from nucleus

why is Ar smaller than Na?

Ar has more protons than Na, higher number protons in nucleus-greater force of attraction-effective nuclear charge

periodic law

when elements are arranged in order of increasing atomic number, their physical and chemical properties show a periodic pattern

core e-

all except valence

shielding

when e- are attracted by nucleus but repelled by other electrons

group trend for shielding

inc going down due to inc in number of energy lvls

period trend for shielding

stays same

Zeff

effective nuclear charge

Zeff=

Z-S; Z is number of protons, S is number of core/shielding e-

group trend for effective nuclear charge

stays same

period trend for effective nuclear charge

inc by 1 when going across

period trend for # of valence e-

inc by 1 when going across

group trend for # of valence e-

stays same