chemistry - groups in the periodic table: group 1 (6.1 - 6.5)

what are group 1 elements called?

alkali metals

6.1 why can some elements be classified as alkali metals/halogens/noble gases based on position in periodic table?

elements in same group:

• same number of outer electrons

• similar chemical & physical properties

• show trends in properties

6.2 alkali metals - physical property (hardness)

soft

6.2 alkali metals - chemical property (melting points)

relatively low melting points

6.3 lithium, sodium, potassium reactions with water

6.4 lithium, sodium, potassium - reactivity pattern

lithium, sodium, potassium = increasing reactivity

6.4 alkali metals - reactivity pattern

reactivity increases down group - top = least reactive, bottom = most reactive

6.5 explain alkali metals reactivity pattern (electronic configuration)

1 valence electron - lose 1 electron when react

down group:

• number of electron shells increases

• force of attraction between + nucleus & - valence electron decreases

• shielding increases

• easier to lose valence electron

• easier to form ions

• reactivity increases