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.
A major disadvantage of a corporation is the double taxation of the corporation's income and of dividends paid to shareholders.
<span>Corporations end up paying taxes twice. The corporation pays tax when it shows a profit. Secondly the corporation pays tax when it pays out dividends to its shareholders. Sole proprietorships and partnerships are taxed as owners of the business. The owners of a corporation are taxed individually from the corporation. The advantage of this is that the owners of a corporation are not taxed on the corporation's profit. </span>
Answer: Strong acid vs weak acid
Strong acids and strong bases refer to species that completely dissociate to form ions in solution.
Explanation: By contrast, weak acids and bases ionize only partially, and the ionization reaction is reversible. Thus, weak acid and base solutions contain multiple charged and uncharged species in dynamic equilibrium.
Mixtures come in many forms and phases. Most of them can be separated, and the kind of separation method depends on the kind of mixture it is. Below are some common separation methods:
There is 1 H atom: (1)(+1) = +1 The oxidation number of O is -2. There are 4 O atoms here: (4)(-2) = -8 So the oxidation state of Cl is +7.
NOTE: The maximum positive oxidation number for chlorine is +7,<span> the same as its group number (VII).</span>