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When air is warmed up, its molecules move faster and faster and as a
result they move further from each other. They still have the same
mass, but they now occupy a larger volume. This means that its density
is smaller.
The opposite when air is cooled off. The molecules slow down, get
closer together, occupy a smaller volume and therefore its density is
bigger.
When air is warmed up, it goes up. Once it's up there, is cools off and
goes back down. Near the heated surface the air gets warmed up again,
goes up, cools down, goes back down, and again and again.
that is called convection cells
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They exist in the outer orbitals
The electron sea model for metals suggest that the valence electrons drift freely around the metal cations.
Answer: B
Explanation
The sea model of electron is used for describing the mechanism of metallic bonding.
The metallic bonding generally occurs between 2 or more metals leading to the formation of alloys.
According to electron sea model, the electrons which contributes to the metallic bond are mostly the valence electrons of the atoms, these valence electrons get de-localized and can move freely around the nuclei of other atoms.
Overall, it seems like nuclei of positive charge is surrounded by sea of negative electrons.
