excited electrons fall to lower energy levels releasing energy as spectra energy is emitted when an electron falls back to lower shells |
53. Identify all the elements in the mixture. [1]
HIGHLIGHT TO SEE THE ANSWER
lithium and strontium Li and Sr |
54. State the total number of valence electrons in a cadmium atom in the ground state. [1]
HIGHLIGHT TO SEE THE ANSWER
2 valence electrons in Cd Cd electron configuration 2-8-18-18-2 |