inorganic chemistry: group 1

name given to the group 1 metals

Alkali metals

3 examples of alkali metals

Li - lithium

Na - sodium

K - potassium

name given to the group 1 metals

Alkali metals

3 examples of alkali metals

Li - lithium

Na - sodium

K - potassium

general alkali metal equation: alkali metal + water →

alkali metal + water → metal hydroxide + hydrogen

why are they called alkali metals

when they react with water they form alkalis

metal hydroxides are alkali

alkali metals also react with o_____, forming different types of _____

alkali metals also react with OXYGEN, forming different types of OXIDES

why do alkali metals tarnish when left in air

react with oxygen, form dull metal oxide layer

why do the alkali metals have similar chemical properties?

all have 1 electron in outer shell (group 1)

why are alkali metals soft

only 1 electron in outer shell, weak metallic bonding, easy to break bonds/cut through

why do alkali metals have such low M/B points compared to other metals

only 1 electron in outer shell, weak metallic bonding, not much energy needed to overcome forces of attraction

why are alkali metals so reactive

only need to lose one electron to become stable

why are alkali metals stored in oil

prevent reaction with oxygen and water vapour in the air

are alkali metals dense or no

low density

formula
observations
speed of reaction
float

2Li(s) + 2H2O(l) → 2LiOH(aq) + H2(g)	2Na+2H2O→2NaOH+H2 same states as prev	K+H2O→KOH+H2(g) same states as prev
effervescence (hydrogen bubbles) does NOT melt	Na melts into ball due to heat released hydrogen produced catches fire ball of Na dashes across surface of water	so much heat: hydrogen burns with lilac flame melts into shiny ball dashes quickly around surface
slowest/relatively slow	middle	fastest
yes	yes	yes

how is lithium’s reaction different from the other two

doesn’t melt, just fizzes steadily

sodium peroxide formula

Na2O2

potassium peroxide formula

K2O2

group 1 metals ____ electrons more easily _____ the group

group 1 metals LOSE electrons more easily DOWN the group

alkali metals lose electrons more easily down the group because:

down the group = more shells

more shells = outer electron is further away from nucleus = weaker attraction (of negative electrons) to (positive) electrons

weaker attraction = electron is more easily lost, less energy needed to overcome those weaker forces of attraction

easier lost electrons means that down the group alkali metals become: (3+1)

down the group…

• softer

• lower boiling points

• more reactive

• (more dense)