Answer:
D) burning a candle
A demonstration that contains both physical and chemical changes will be BURNING OF A CANDLE.
<em>This is because when a candle is lighted up, on the top of it (where we see flame) the oxygen and other gases present around will be chemically changed (burned up)</em>
<em>When the wax in the top of the candle will get melted due to the heat of the fire a physical change takes places.</em>
Since chromium has 24 as its atomic number (which mean that it has 24 proton and 24 electron in neutral ground state), the electron configuration for the chromium would be :
1s^2 , 2s^2 , 2p^6 , 3s^2, 3p^6 , 3d^5 , 4s^1
<span>You can see mars in the night sky because it is a very bright planet. Mars is as bright, or brighter than the stars. Yes, all planets are pretty bright, but mars in beyond bright along with jupiter, mercury, etc. Hope this helped! :)</span>