The electron configuration for this atom is Calcium, which has 2 valence electrons.
Explanation:
Following the periodic table and with the electron configuration, you will end up with calcium, which has 2 valence electrons. (Always follow the electron configuration from left to right! It begins at hydrogen, then to helium... and so on.)
The answer is C. They lower the activation energy of an elementary step of a reaction This makes the reaction rate to increase since less energy is required to make a reaction occur.
