No, physics does not suggest an exact pace in which a chemical compound will travel. It will matter in external forces as well as the median it is travelling through.
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.
2H2O = 2H2 + O2.
<h3><u>Explanation</u>:</h3>
Balancing equations is very essential because of the fact that it represents the stoichiometric quantities of the reactants needed to react to form the product. The ratio of the weights of reactant and product are also very well understood from this.
Here in this equation, the water is broken into hydrogen and oxygen. The balanced reaction is
2H2O = 2H2 + O2.
Two moles of water is broken down into 2 moles of hydrogen and one mole of oxygen.
