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.
I think this one is the organelles.
Answer:
Impacts on Ocean Life
Coral Reefs.
Oysters, Mussels, Urchins and Starfish.
Zooplankton.
Plants and Algae.
Fish.
Explanation:
Answer:
neutrons
Explanation:
isotopes have the same number of protons nut different number of neutrons. the difference in thr mumber of neutrons give them their uniques properties.
Answer:
oxygen, water and sugar are the out come of photosynthesis
