Please provide the choices here.
The similarity of the bands in the crystal of a metal to the atomic orbitals can be explained by the band theory of metals. In an atom, when the electrons get excited, the electrons jumps to a higher orbital so as to reach equilibrium. This is analogous to the electrons in the metals which also jumps to another band once excited by an external energy (e.g. electrical energy).
Definitely Calcium Chloride.
All the others are covalent.
Answer: pressure
Explanation:
the gas is changing because of the torch being lit inside the hot air balloon which make the volume change when the hot air balloon get put up
