Group 1 Flashcards

All 8 cards in this deck

What are the elements in group 1 of the periodic table called?

The alkali metals.
e.g. lithium, sodium, potassium, rubidium (Rb), caesium (Cs), francium (Fr)

What do you observe when a small piece of sodium is added to water?

It floats, melts into a ball, moves around on the surface, fizzes (effervescence) and quickly disappears.

Give the balanced symbol equation, with state symbols, for sodium reacting with water.

$2\mathrm{Na}(s) + 2\mathrm{H_2O}(l) \rightarrow 2\mathrm{NaOH}(aq) + \mathrm{H_2}(g)$
The metal hydroxide solution is alkaline, turning universal indicator purple.

In terms of electrons, why are lithium, sodium and potassium placed in group 1, and what ion do they form?

They each have 1 electron in the outer shell, which they lose to form a +1 ion.

Put lithium, sodium and potassium in order of reactivity with water, most reactive first.

Potassium, then sodium, then lithium.
Potassium fizzes most vigorously, moves fastest and burns with a lilac flame; lithium reacts least vigorously.

True or false? Caesium reacts less vigorously with water than potassium.

False. Reactivity increases down group 1, so caesium reacts far more vigorously than potassium — explosively.

Why does reactivity increase going down group 1?

Each element down the group has more shells, so the outer electron is further from the nucleus and more shielded, making it easier to lose.

True or false? Alkali metals are soft enough to be cut with a knife.

True. Group 1 metals are soft, and they also have relatively low melting points.