abeka phy sci 9 section 13.4

quiz tmr (3/13)

valence electrons

located on outermost electron shell

octet rule

__**eight**__ electrons in outermost electron shell (valence electrons)

periodic law

elements show regular and repeating properties when arranged by increasing atomic number

periodic table of elements

table arranged by atomic number and number of valence electrons

period

a row on periodic table

group

arranged by same number of valence electrons

1, 2, 13-18

what are the main group elements?

metals

hard, dense, shiny solids

nonmetals

 poor conductors of electricity; gasses and liquids

semimetals

solids with characteristics between nonmetals and metals

alkali metals

group one; very soft, shiny metals

alkali earth metals

group two; harder, denser and less reactive

transition metals

groups 3-12; strength and durability

inner transition metals

between groups 3 and 4 (under table); radioactive

13-16

what are the mixed groups?

carbon

found in graphite and diamond

halogens

group 17; “salt formers”

noble gasses

 group 18; found in their pure states in nature