Trends in Group 1
As you go down Group 1, does reactivity increase or decrease, and why?
Reactivity increases. Because outer electrons are more easily lost because the atoms get bigger, causing the force of attraction to reduce.
Alkali metals belong to which group in the periodic table, and what does their single valence electron imply about their reactivity?
Group 1; their single valence electron makes them highly reactive and eager to lose it.
Which alkali metal is used in rechargeable batteries, and why is it chosen?
Lithium is lightweight and is high-energy density.
Explain the trend in melting and boiling points down Group 1 in terms of metallic bonding.
Melting/boiling points decrease due to weaker metallic bonds as atoms get larger.
What type of ion do alkali metals form when they react, and why is this energetically favorable?
They form +1 cations; losing one electron gives them a stable noble gas configuration.
Which alkali metal is used in street lighting, and what property makes it suitable?
Sodium produces bright yellow light
Do alkali metals become harder or softer down the group, and why?
They become softer because larger atoms have weaker metallic bonding.
Which alkali metals produce crimson red, bright yellow, and lilac flames?
Lithium → crimson red, Sodium → bright yellow, Potassium → lilac.
Which alkali metal is used in fertilizers, and what role does it play?
Potassium is an essential nutrient in fertilizers.
What happens to density as you go down Group 1, and why is lithium an exception?
Density generally increases, but lithium is anomalously low due to its small atomic mass.
How can flame tests be used to identify alkali metals, and what limitation do they have?
Flame tests identify alkali metals by characteristic colors, but overlapping emissions (e.g., sodium’s strong yellow) can mask others.
What alkaline metal reacts with a group 7 non-metal to form an edible salt?
Sodium and Chlorine to form Sodium Chloride (Table salt)
Why does reactivity increase as you go down the group, in terms of atomic radius?
Larger atomic radius causes the attractive forces to reduce, making it easier to lose the valence electron.
What do alkali metals produce when they react with water, and why is this reaction considered dangerous?
They produce metal hydroxide and hydrogen gas; the reaction is exothermic, and the hydrogen can ignite or explode, making it dangerous.
Why do alkali metals have such varied uses, despite being in the same group?
Their varied reactivity, ion sizes, and physical properties allow different applications.