Agroup of students are wandering around a room. when their teacher claps, the students sit down wherever they are.

this situation best models the formation of which type of solid?

an amorphous solid because the particles do not have a regular structure
an amorphous solid because the motion of the particles stopped
a crystalline solid because the moving particles lock into fixed positions
a crystalline solid because the particles have a long-range order

Amorphous solids.

Explanation:

The students sit down wherever they are means that the movement of students has been stopped thus they will be behaving like particles in a solid.

Now as the students were irregularly arranged thus the solid will be amorphous.

there are two types of solids:

Crystalline solids: they have regular arrangement of particles in them.

Amorphous solid : they have random arrangement of particles in them.

alkaline metals are lithium, sodium, rubidium, potassium, cesium and francium.

alkali metals have electronegativity from 0.7 to 1, lowest in periodic table of elements, which means that alkali metals (i group in periodic table) has positive oxidation number in compounds.

electronegativity is a chemical property that describes the tendency of an atom to attract a shared pair of electrons towards itself.

alkaline metals (far left in main group) have lowest ionizations energy and easy remove valence electrons,

for example, potassium is the alkali metal and has a single valence electron in the outer electron shell.

electron configuration of potassium is: ₁₉k 1s²2s²2p⁶3s²3p⁶4s¹.

they can not exist alone in nature, because they are very reactive.