Group I PropertiesCambridge IGCSE Chemistry: Flashcards

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What are the Group I elements also known as?

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What are the Group I elements also known as?: The alkali metals. Group I elements are called alkali metals because they react with water to form alkaline solutions.
Describe the physical state and general appearance of Group I alkali metals.: Group I metals are relatively soft solids that can be cut easily with a knife. They have a shiny, metallic appearance but quickly tarnish when exposed to air.
What is the trend in melting point as you go down Group I from lithium to potassium?: Melting point decreases down Group I. Lithium has the highest melting point (~180°C), and potassium has the lowest (~63°C).
What is the trend in density as you go down Group I from lithium to potassium?: Density increases down Group I. Lithium has the lowest density (~0.53 g/cm³), and potassium has a higher density (~0.86 g/cm³).
What is the trend in reactivity as you go down Group I from lithium to potassium?: Reactivity increases down Group I. Lithium is the least reactive, sodium is more reactive, and potassium is the most reactive Group I metal shown in IGCSE.
Explain why reactivity increases down Group I in terms of electron configuration.: As you go down Group I, the outer electron is further from the nucleus and shielded by more inner electron shells. This makes it easier to lose the outer electron, so reactivity increases.
What type of bonding do Group I elements typically form?: Group I elements form ionic bonds, readily losing their single outer electron to form +1 ions (cations).
Name the three Group I alkali metals required for IGCSE Chemistry.: Lithium (Li), sodium (Na), and potassium (K).
How does the softness of Group I metals change going down the group?: Group I metals become softer going down the group. Lithium is relatively hard compared to sodium and potassium, with potassium being the softest.
What is the electronic configuration of sodium?: 2,8,1. Sodium has one electron in its outer shell, which it readily loses to form Na⁺ ions.
Given that rubidium is below potassium in Group I, predict whether rubidium would be more or less reactive than potassium.: Rubidium would be more reactive than potassium, as reactivity increases down Group I due to the outer electron being easier to remove from elements lower in the group.
Given that francium is at the bottom of Group I, predict its melting point relative to potassium.: Francium would have a lower melting point than potassium, as the trend shows melting point decreasing down Group I.
What happens to the atomic radius as you go down Group I?: Atomic radius increases down Group I. Each element has an additional electron shell, making the atoms progressively larger.
Explain the relationship between atomic radius and reactivity in Group I.: As atomic radius increases down Group I, the outer electron is further from the nucleus and more shielded. This makes it easier to lose, so reactivity increases with increasing atomic radius.
What would you predict about the reactivity of an unknown Group I metal positioned between sodium and potassium?: It would have a reactivity between that of sodium and potassium. It would be more reactive than sodium but less reactive than potassium, following the trend of increasing reactivity down the group.