Electrons in an atom can be classified as core electrons and valence electrons. Valence electrons are those electrons which are present in valence shell and participates in bond formation. While, Core electrons are all remaining electrons which are not present in valence shell, hence not take part in bonding.
Atomic number of Selenium (Se) is 34 hence it has 34 electrons with following electronic configuration;
1s², 2s², 2p⁶, 3s², 3p⁶, 4s², 3d¹⁰, 4p⁴
From electronic configuration it is found that the valence shell is 4, and the number of electrons present in valence shell are 6. So,
Core Electrons = Total Electrons - Valence Electrons
Core Electrons = 34 - 6
Core Electrons = 28
Result:
There are 28 core electrons in Selenium.
<span>Hydrogen carbon and oxygen commonly form covalent bonds.
</span>
HOPE THIS HELPS!
There are three subatomic particles known: (1) electron which is found outside the nucleus of an atom and (2 and 3) protons and neutrons which are both inside the nucleus. As they are outside the nucleus, it is easier to transport electron than any other subatomic particle. Thus, atom and its ion differ in the number of electrons.
The answer is D. Okay l hope this helps
I completely understand your gripe. I also believe that you are the better option. It will only take time until she is yours, despite your parent's views. Keep it up
