Chemistry291

 Each carbon atom has 4 valence electrons. Explanation: To find out valence electrons of carbon,you need to look at the periodic table.For main group element,the group number is equal to the number of  valence electrons. The element carbon is in group 4A,that is why it has four valence electrons(Just skip the letter A).If you say carbon is in group 14,then you need to consider unit place digit 4 for valence electrons. Now I will show you how to find valance electrons of carbon from electron configuration. The atomic number of carbon is six.So it has six protons and six electrons. If you write electron configuration of carbon,the you will get the following: C ---> 1s² 2s² 2p² We know that valence electrons are the electrons that are found in the valence shell.Valence shell is the outter most shell. We can easily found the outter most shell or valence shell considering the highest value of principal quantum number,n. From C electron configuration,we see that the highest value of n is

7 Explanation: Seven d electrons are found in cobalt.Here is the way to find the number of d electrons  in cobalt. The electrons that are found in d subshell or orbitals are called d electrons. The atomic number of cobalt is 27.This means that cobalt has 27 protons and 27 electrons. Now write the electron configuration of cobalt: ₂₇Co =1s²2s²2p⁶3s²3p⁶4s² 3d⁷ In  3d⁷ subshell,we are getting 7 electrons.So,in cobalt you get seven d electrons.