Answer is: D) Light is emitted from an atom as an electron falls from an excited state to the ground state releasing a photon.
Electrons can jump from one energy level to another, absorbing or emitting electromagnetic radiation with a frequency ν (energy difference of the levels).
When electron jump from higher to lower energy level (shell), it emitting (releasing) energy.
For example, when the electron changes from n=4 (fouth shell) to n=2 (second shell), the photons are emitted.
D) reacts with oxygen
All other are physical properties.
Most likely it’s crystalline structure, which makes it small granules that are soluble in water. Most, if not all, ionic compounds are salts. And salts dissolve in water.
Hope that’s correct
VESPR (<span>Valence Shell Electron Pair Repulsion) is used to determine the shape of the molecules based on their number of electron pairs and how they interact with each other via repulsion. Different numver of electron pairs will form different shapes, e.g. 0 pairs = linear, 1 = pyramidal...</span>
1000000 nanometer makes 1 millimetre
23500000/1000000= 23.5 mm